They are extruded acrylic tubes, overall diameter is 6/8". Thickness of the wall of the tube is 1/8". From my little experience, 1/8" thickness is harder to bend but it comes out neat and better looking than if you try bending a 1/16" thickness tube. The secret to bending these tubes lies in the heating process. Most people would recommend using a heat gun to make a bend but the source of heat that I used in bending my tube was my stove. My stove measures about 12 inches in diameter, so that's a long enough length to heat up the tube for bending. I place a brick at each end of a stove, then the tube would lay on top of the bricks. Turn the stove on "high", as the tube is being heated, I'm constantly turning the tube, so that there would be an even heating of the tube, after about at least five minutes, the tube would become soft and bendable. Base on your own judgement of how soft the tube is and if it's bendable, if it is, take the tube away and bend it into a U shape. It would be easier to bend the tube into a U shape if you have something that is already in the shape of a U and just use that as a guide.