RokSiEu, that looks like another leaky piece of junk with overstated specifications waiting to make your day.
I would rather buy a flashlight designed and built by a real manufacturer. Sofirn has many diving torches, for example (but better look for reviews before buying, like this Sofirn SD05 review by Nachtfeuerzeug). ThorFire, another nice brand, has its ThorFire S1 diving flashlight recommended at GloboSurfer as a best pick.
Anyway, feel free to ask but wait for more experienced users in these concerns to chime in. 