Water Resistance: Watches are ranked Ⅰ through Ⅴ according to water resistance. Check the ranking of your watch in the following chart to determine proper use.
Rank
Case Designation
Splashes, Rain,etc.
Swimming, Car-washing,ect.
Snorkeling, Diving,etc.
Scuba Diving
Ⅰ
/
No
No
No
No
Ⅱ
WATER RESISTANT
Yes
No
No
No
Ⅲ
50M WATER RESISTANT
Yes
Yes
No
No
Ⅳ
100M WATER RESISTANT
Yes
Yes
No
No
Ⅴ
200M WATER RESISTANT
Yes
Yes
Yes
Yes
Notes: Ⅰ Not water-resistant. Avoid all moisture. Ⅲ Do not operate buttons underwater. Ⅳ If watch is exposed to salt water, wash thoroughly and wipe dry. Ⅴ Usable while scuba diving (Except at depths that require helium-oxygen gas). ● Some water-resistant watches feature leather bands, be sure to dry the band thoroughly if it becomes wet. Prolonged wearing of the watch with a wet band may reduce the life of the band and cause it to discolor. It may also cause a skin reaction. Which rank can enable people to dive at the depths that need helium-oxygen gas