Not a strip. It is a small housing. Or I guess it is a strip in a case, I'm not really sure.
No power supply needed. Plug and go.
It's a nice option and yes completely waterproof.
They are nice! I need led lighting for a cage but since you posted that for the op I need to decide if I wanna buy a roll from amazon and do all my cages or buy one of those for each one. Oh great now I have to think lol