Well most of the sports reps are normaly pretty good out of the box, best to get it tested first but i never do i just chech ther back is on tight and the crown screwed down and dive in,
so far no problems with my:-
Railmaster
Aqua Terra
SOSF
177H
Noobmarina
Cheep seadweller
EX 2
Silix PO
As a general rule i use for my self, if it has a screwed crown and screwed case back and the crystal is installed flush and flat i will give it a go, please dont take this as a rule for all, i take a risk in life and a risk when i jump.