You may have heard the terms “water resistant” and “waterproof” concerning watches, but have you ever considered exactly what these terms mean? Although the two terms have entirely different meanings, they are often used interchangeably. Simply put, a waterproof luxury copy watch can withstand contact for a certain period or under certain conditions. In contrast, a “water resistant” watch is supposed to be theoretically impermeable to water.
But the truth is that no watch can guarantee permanent water resistance. Even the finest diving replica watches on the planet, such as the Rolex Sea-Dweller, are susceptible to the aging process and extreme conditions. It is unreasonable to assume that a product made of physical materials will not be affected by its physical environment over time.  
One of the leading causes of the failure of “water resistant” watches is the degradation of the seals designed to ensure a seam-free construction. This seal is usually made of rubber or plastic that can be weakened or eroded in extreme heat or cold. One reason why it makes sense to have your fake watch serviced every few years is to ensure that the seal is functioning as it should.
But this is part of the issue surrounding the general public’s understanding of water resistance and waterproof. Many of the tests performed at watchmakers are dry and static tests. Instead, substantial external air pressure is applied to the watch and measured for leaks or deformation. If the watch passes a test of this nature, it can be said to be water-resistant. In practice, however, this may not mean as much.
Fluctuations in temperature can cause real problems for a watch’s water resistance. Components (and the gaps between them) can expand in warm weather. Add to that active immersion or moving water (like you’d expect to find in a shower or hot tub), and that’s a bad combination for a watch to hope to encounter.
There are three ways to express the depth your replica watch is testing for. The most common unit of measurement is the “meter.” It is usually represented by the letter “M”. Perhaps the second most common way to communicate depth levels is atmospheric pressure. The atmosphere is denoted by the abbreviation “ATM.” One atmospheric pressure is roughly 10 meters, so 10 ATMs is the same as 100M.
The most common depth ratings are 30M, 50M, 100M, 200M, and 300M. Outside of these depths, there are 500M, 1000M, and even more profound ratings, but they are usually reserved for specialized dive tools. When can you safely jump over a puddle, into a bathroom, or a pool? Heaven forbid you to find yourself tempted to shell out for a hot tub, but if this sounds like the kind of thing you might find yourself doing, you might want to invest in a seriously thick outfit.