GFunk bar clamps 32mm
The G Funk is a two part clamp design that's designed to allow you to fit a Strapdeck in front of or below your bars in order to strap something like a drybag to it for solid-no-wobble-or-shake carrying goodness. Clamps are 32mm (actually 31.8mm) to fit either side of your stem on almost all modern bars.
**NOTE THIS IS FOR THE 2 X CLAMPS ONLY, STRAPDECK AND STRAPS ARE AVAILABLE SEPARATELY**
There's a little bit of extra info on drJ0n's blog that you may find useful here :
31g for the pair including mounting hardware
The best StrapDecks for this is are the Double Trouble Triple or the Large, the recommended straps (alu or nylon) would be 20" if going round your pack and the Strapdeck, 25" if going round the bars too.