- Your Steel can withstand a pressure similar to that of a 50 m (165 ft) depth. You can, therefore, use it when dishwashing, splashing or swimming. however, it can't be used for diving or snorkeling.
- Avoid long exposure to salt water. Make sure you rinse your watch with fresh water after spending time swimming in salted water.
- Avoid exposure to any chemical products such as solvents, detergents, perfumes or cosmetics. They may damage the wristband or the casing of the watch.
- Avoid extreme atmospheres (e.g., saunas or steam rooms)
- The aging of the materials may affect the waterproofness of the watch. Water resistence cannot be permanently guaranteed.
https://support.withings.com/hc/en-us/sections/4411850657041-Steel
https://support.withings.com/hc/en-us/sections/200609497-FAQ