These are sold under numerous brands, named and unnamed, through Alibaba or Amazon but it's visibly the same build. These are notable because for any sort of serious diving, you want 10k lumens or more.
Specs:
Divers have reported quality control issues where some arrive perfectly fine, but some leak or are dead-on-arrival. The canister uses O-rings and you'll want to protect them further with grease. You may also want to seal the batteries with silicone.