When you don't want it to leak and you want it to last there is only one choice in underwater light construction-- FORGED BRASS!  Forged brass is less porous than cast brass.  Starts with one chunk of solid brass that is heated red hot and then forged into this shape-- a true heavy weigh, quality underwater light.  Solid forged brass lighting fixture for underwater use in fountains and water features.  12v and fully submersible.  Tight mechanical screws onto o-ring seals, pressure fittings where cable enters fixture.  Solid forged brass construction is the best material for underwater use, especially in chlorinated and chemically treated water features where aluminum will corrode.  Use MR16 lamp in 20w, 35w or 50w.  Bracket Diameter is  3 3/4" and fixture is 6" high