What types of water-resistant watches are there?

"WATER RESISTANT” is a quality specification for water-resistant watches based on the description of JIS (Japan Industrial Standards) and ISO (International Organization for Standardization).

"WATER RESIST” and "W.R.” are the abbreviated forms of "WATER RESISTANT.”
According to JIS, the water resistance for daily use is indicated by "bar” (atmospheres) and the water resistance for diving is indicated by "m” (meters). 

It is important to read carefully the instruction manual to understand the handling instructions and precautions before use regardless of the degree of water-resistance of the watch.

The various types of water-resistant watches and their basic precautions are outlined in the table below. Make sure that you choose a watch that suits your needs. 
Examples of water-resistant indications shown in the table below are indicated either on the dial or on the case back.

Name	Specifications	Examples of water-resistant indications	Uses/precautions in handling
Watch for mixed-gas diving (JIS class 2 diver's watch)	200m - 1000m Water resistant	HE-GAS DIVER'S 300m	The water resistance is as high as it can withstand diving to the depth of water indicated (example: 300m). This watch equipped with devices required for measuring the diving time and decompression time, such as a rotating bezel, can be used for deep-sea diving (mixed-gas diving) using the mixed gas of helium and oxygen for respiration.
Watch for air diving (JIS class 1 diver's watch)	100m - 200m Water resistant	AIR DIVER'S 100m	The water resistance is as high as it can withstand the pressure to the depth of water indicated (example: 100m) and longtime underwater use. This watch equipped with devices required for measuring the diving time and decompression time, such as a rotating bezel, can be used for shallow-water diving (scuba diving, etc.,) using compressed air in a cylinder for respiration. This cannot be used for mixed-gas diving.
Enhanced water resistant watch for daily use (JIS class 2 water resistant watch)	Water resistant to 20 bars	WATER RESIST 20 BAR WATER 20BAR RESIST W.R.20BAR	This can be used by people who do water sports (swimming, sailing, fishing, etc.,) and skin diving. Do not use it for mixed-gas diving or air diving.
	Water resistant to 10 bars	WATER RESIST 10 BAR WATER 10BAR RESIST W.R.10BAR
	Water resistant to 5 bars	WATER RESIST 5 BAR WATER 5BAR RESIST W.R.5BAR	This can be used by people who often touch water (fishery, agriculture, car washing, restaurants, etc.,) and who do water sports (swimming, sailing, fishing, etc.). Do not use it for skin diving, mixed-gas diving, or air diving. Even if the water resistance is 5 bars or more, avoid directly showering or applying tap water to it under high pressure.
Water resistant watch for daily use (JIS class 1 water resistant watch)	Water resistant to 2-3 bars	WATER RESIST W.R.	This can withstand perspiration, face washing water drops, rain, etc., in daily life, but cannot be used for water-using works, water sports, skin diving, and other types of diving. Do not use it under conditions in which the water pressure changes sharply.
Non-water resistant watch	In the case of no marking of WATER RESIST on the case back, avoid direct contact with water.