Summary This is my idea of an watercooling block for cheap M6 tubes. Right now it is highly experimental. I wanted to reduce weight and size of my hotends to the smallest possible ammount. If this thing works well you can completly remove the heatsinks on hotends. Then a hotend just assembles from this block, an 1$ china tube, heatblock and nozzle. It is 16mm height and should be printed as fine as any possible to make the tubes strong enough. Features Grooves at bottom and top to fit an rubber small size (16mm height, 16mm width) 2,5 circles to let the water cool as much as possible surface Update 2015-10-10 added inprint supports. So the slicer doesn`t have to try print support inside of the tubes Print Settings Rafts: Doesn't MatterSupports: YesResolution: .1 or as fine as possibleInfill: 100% Notes: Should be printed solid and fine to withstand mechanical movement and heat from heatblock. How I Designed This Made entirely with Designspark Mechanical.