Water Resistance Explained
Water Resistant is a common mark stamped on the back of wrist watches to indicate how well a watch is sealed against ingress of water. It is usually accompanied by an indication of the static test pressure that a sample of newly manufactured watches was exposed to in a leakage test. The test pressure can be indicated either directly in bars, or (more commonly) as an equivalent water depth in meters (in the United States sometimes also in feet).
An indication of the test pressure[1] in terms of water depth does not mean a water resistant watch was designed for repeated long term use in such water depths. For example, a water resistant watch marked at 30 meters depth cannot be expected to withstand activity for longer time periods in a swimming pool, let alone continue to function at 30 meters under water. This is because the test is conducted only once using static pressure on some of the newly manufactured watches. The test for qualifying a diving watch for repeated usage in a given depth includes safety margins to take factors in account like aging of the seals, rapidly changing water pressure and temperature, as well as dynamic mechanical stresses encountered by a watch. Also every diving watch has to be fully tested for water resistance.
Watches are classified by their degree of water resistance which, due to the absence of official classification standards, roughly translates to the following (1 metre ≈ 3.29 feet):[5]
| Water resistance rating | Suitability | Remarks |
| Water Resistant or 50 m | Suitable for swimming, white water rafting, no snorkeling water related work, and fishing. | NOT suitable for diving. |
| Water Resistant 100 m | Suitable for recreational surfing, swimming, snorkeling, sailing and water sports. | NOT suitable for diving. |
| Water Resistant 200 m | Suitable for professional marine activity and serious surface water sports. | NOT suitable for diving. |
| Diver’s 100 m | Minimum ISO standard (ISO 6425) for scuba diving at depths NOT suitable for saturation diving. | Diver’s 100 m and 150 m watches are generally old(er) watches. |
| Diver’s 200 m or 300 m | Suitable for scuba diving at depths NOT suitable for saturation diving. | Typical ratings for contemporary diver’s watches. |
| Diver’s 300+ m for mixed-gas diving | Suitable for saturation diving (helium enriched environment). | Watches designed for mixed-gas diving will have the DIVER’S WATCH L M FOR MIXED-GAS DIVING additional marking to point this out. |
Learn more about water-resistant classifications on Wikipedia.
Watch Cases
Watch cases, the housing of the timepiece that contains the internal movement, can be made out of anything that’s durably solid, but today’s cases are primarily made of stainless steel.
Stainless steel is quite durable and contains a bit of chromium to help protect the steel from corrosion and rust. Typically silver in color, it can be plated with a thin layer of gold (about 10 microns, or 1/1000 of a millimeter in thickness) in whole or in part for added accent. You can also find stainless steel cases in different colors, thanks to a process called ionic plating or PVD (physical vapor deposition) which usually gives it a matte finish.
The most popular form of gold is still yellow gold, but rose gold, featuring a pinkish tint due to a higher concentration of copper in its alloy mix, is gaining in popularity. When shopping for gold watches, pay attention to the fineness (or purity) of the gold as expressed in karats. A single karat equals 1/24 of the pure metal, so an 18 karat gold watch translates to 75 percent pure gold (whereas 14 karat gold equals 58 percent).
Titanium has become popular in higher-end watches as it’s a bit more expensive and harder to work with. Offering a lighter shade of silver, titanium is 50 percent lighter than steel, but 30 percent stronger. For watch enthusiasts who have allergic reactions to stainless steel, titanium is an excellent alternative as it doesn’t contain nickel (the allergen found in stainless steel). It’s also a great choice for diving and water sports as it’s very resistant to salt water corrosion. On the downside, it’s a bit more apt to picking up scratches.
Additionally, you’ll find watch cases made of precious metals, such as platinum (used in luxury watches) and sterling silver, ceramic, tungsten, aluminum (also very corrosion-resistant), and carbon fiber. Sport watch cases are typically made of hardened rubber, plastic, or resin, and are a good option for use during more rugged activities.
Shapes
Wrist watches come in a few basic shapes: round, square, and rectangular. A fourth popular shape is Tonneau, which has a tall orientation with a flattened top and bottom, and bulging sides that resemble a barrel. Round watches are the direct descendent of the pocket watch and are the most popular shape. The majority of sport watches will be circular as it’s the shape that’s easiest to make water-resistant. Square watches provide more of a canvas for adding decoration to fashion watches. Rectangular watches are considered dressier as they can be better hidden under the sleeve. Tonneau-shaped watches present a unique retro style and are also considered dressy thanks to their slimmer profile.
Sizing
Watches are typically measured in millimeters (mm), which might not be familiar to those of us without a lot of metric system experience. Any given watch typically has three measurements: case diameter, case thickness, and band width.
At Amazon.com, you’ll find these measurements listed in the Product Specifications section of each product detail page.
Watch Movements
The movement of a watch refers to the mechanics that power the ticking of the timepiece, and there are two main choices when it comes to analog watches (watches with hour hands and are not digital), quartz or automatic.
What you choose really comes down to what you’re looking for in a watch. There are many ways to look at what’s attractive about both types of watches, but one way to look at it is the quartz watch as more practical and the automatic watch as more emotional.
Quartz
The majority of watches made today utilize the vibrations of a tiny quartz crystal to maintain timing, with the power coming from a battery that needs to be replaced every 2 to 3 years. Watches with quartz movements are more accurate, losing about a minute of accuracy over a year, and they can have either analog or digital displays, or both.
Solar
Some quartz watches are solar-powered, storing light that enters through the dial face, which eliminates visits to the jeweler to change the battery.
Atomic
Atomic watches can be calibrated daily (or several times a day) via radio signals from an atomic clock (such as the one located in Fort Collins, Colorado). Atomic time is measured through vibrations of atoms in a metal isotope that resembles mercury. The result is an extremely accurate time that can be measured on instruments. Radio waves transmit this exact time throughout North America, enabling some atomic watches to correct themselves to the exact time.
Automatic
Automatic watches are made up of about 130 or more parts that work together to tell time. Automatic movements mark the passage of time by a series of gear mechanisms, and are wound by the movement of your wrist as you wear it. The gear train then transmits the power to the escapement, which distributes the impulses, turning the balance wheel. The balance wheel is the time regulating organ of a mechanical watch, which vibrates on a spiral hairspring. Lengthening or shortening the balance spring makes the balance wheel go faster or slower to advance or retard the watch. The travel of the balance wheel from one extreme to the other and back again is called oscillation. Lastly, automatic movements come in different types, including movements that are Swiss-made, Japanese-made, and more.
Also referred to as self-winding, watches with automatic movements utilize kinetic energy, the swinging of your arm, to provide energy to an oscillating rotor to keep the watch ticking. They’re considered more satisfying to watch collectors (horologists) because of the engineering artistry that goes into the hundreds of parts that make up the movement. If you do not wear an automatic watch consistently (for about 8 to 12 hours a day), you can keep the watch powered with a watch winder (a great gift for collectors). You should refer to your owner’s manual for recommended service intervals.
Automatic Watch Maintenance
Although automatic (also called “mechanical”) watches do not have batteries, some easy-to-follow maintenance is necessary for continued and long-lasting good use.
Self-winding automatic watches depend on the movement of the arm to operate and do require some winding, even if you wear your watch on a daily basis.
If you wear your automatic watch every day, it is best to wind it once every two weeks to keep the wheels in motion and oil fluid. Simply wind the crown (the same knob used to adjust the time and date) until you meet slight resistance If you do not wear your automatic watch every day, you should try to wind it at least twice a week to ensure continuous operation, as well as keeping the inside mechanism in complete running order.
If you have a mechanical watch, it is best to wind it at the same time every day. This is extremely beneficial for the mechanism. You may want to make it a routine, winding it every morning when you wake up. If your watch has a day/date function, avoid setting the day and/or date at night. The day-date mechanism is activated during the nighttime hours and could be disrupted if set at this time.
What is the difference between a Mechanical Movement and an Automatic movement?
A mechanical movement is a movement based on a mainspring which when wound slowly unwinds the spring in an even motion to provide accurate timekeeping. As opposed to a manual mechanical watch which needs to be wound on a consistent basis, an automatic mechanical requires no winding because of the rotor, which winds the mainspring every time you move your wrist (see our section on automatic watch maintenance for more details).
Other Movements
Eco-Drive
Eco-drive was created by Citizen and has earned recognition in the watch industry as a leader in ecologically-friendly timekeeping. Citizen Eco-Drive runs continuously in any kind of light (natural or artificial) for a lifetime of use without a battery. The Eco-Drive movement absorbs light through the crystal and dial. Inside the watch, a solar cell converts the light to the energy required to make the watch run.
Kinetic
Referring to the Seiko line of Kinetic watches, this innovative technology has a quartz movement that doesn’t use a battery. Movement of the wearer’s wrist charges a very efficient capacitor that powers the quartz movement. Once the capacitor is fully charged, men’s models will store energy for 7-14 days without being worn and ladies’ models will store energy for 3-7 days. The watch alerts the wearer to a low capacitor charge when the second hand starts to move in two-second intervals.
Over the past 20 years, Seiko has created a suite of Kinetic movements, each bringing unique features to the consumer.
It was at the 1986 Basel Fair that Seiko unveiled its first Kinetic prototype. Introduced under the trial name of AGM, it was the first watch in the world to convert kinetic movement into electrical energy. It was the first step in a development that, 20 years later, has made Kinetic synonymous with environmental friendliness, high performance and long-lasting convenience to a generation of users worldwide. From the launch in 1988 of the first commercially available watch (then under the new name AGS) until today, over 8 million Kinetic watches have been sold (as of 2007).
In 1998, Kinetic Auto Relay was released, extending the ‘at-rest’ operating period of the watch to a remarkable 4 years. 1999 brought the launch of the Ultimate Kinetic Chronograph, a masterpiece which fused the very best of Seiko’s mechanical and electronic watchmaking skills, and in 2003, another Kinetic Chronograph was launched. At Baselworld 2005, the Kinetic Perpetual made its first appearance, combining Kinetic convenience and longevity with a perpetual calendar, correct to the year 2100. Most recently in 2007, Seiko’s emotional technology Kinetic Direct Drive was introduced.
Swiss Movements
It might be stereotypical, but it’s true. Many of the world’s finest and most accurate timing movements, be they quartz or automatic, are created in Switzerland. Swiss-manufactured movements are found in a wide swath of watches sold worldwide, but a timepiece can only be awarded the coveted Swiss-made label if the movement is made and then subsequently encased in Switzerland.