I got it from Northern, it's a Jobox made by Delta. The whole thing loaded with tools weighs almost exactly 1000 lbs. but it's made to fit like a glove in that bed. I have a board across the front to "shim" it to come 1'inch inside the tailgate (and keep it from squeeking against the bed) and I drop a 2x4 between the skid and wheel wells to wedge it in side to side. It doesn't move, being on a rubber mat probably helps too.