If the words "30M waterproof" or "3aatm" are engraved on the back of the case, the watch you designed and manufactured can withstand waterproof pressure as high as 30m, such as being splashed by water or caught in the rain occasionally, but it is not designed and manufactured for swimming or diving.
Waterproof performance (50m waterproof /5 atm)
If the words "50M waterproof" or "‘5 ATM'" are printed on the back of the watch, the watch you designed and manufactured can withstand the waterproof pressure as high as 50m. Generally suitable for swimming, showering and water skiing (note: avoid the above activities in chemical and corrosive water).