http://www.jacksrbetter.com/Tri-Glides.htm

Most webbing locks you find are intended to cinch down a sleeping bag or the like.. these are cut from thick aluminum. I have used them many times, with my 210lb fat @$$ and whatever else I brought along - zero slippage. I tried rings and found it too tricky to get the straps right on top of each other to justify against the admitted pain of feeding webbing through a ladder lock.