The dust proof and waterproof Apple Watch case by Catalyst​ ​has a military specification of being water resistant up to 50m.
It doesn’t spoil all of Apple Watch’s functionality,
and is also compatible with charging.
It comes in 3 colours,
‘Sea’, ‘Mountain’, and ‘Snow’, which for now is the best.
Domestic handling in Japan is by​ ​Trinity.​ ​