Looks like a standard outdoor or pond lighting fixture, found at your local hardware store.
Manufactured to be waterproof to perhaps 2 metres, perhaps more depending on the lens thickness and quality of the fittings. You could make this work deeper with a little thought. The light emissions for the size of that thing and what is available could be a lot brighter, especially if you're going to keep it as a canister torch. A canister torch that size could be 20-40watts, or even more.