Originally Posted by thook

That pipe insulation is measured for the inside diameter. IOW's, it's measured for what size pipe it's intended to insulate. So, you will have trouble finding something small enough. Perhaps some clear, flexible vinyl tubing? It should have the rigidity to give the appearance of an inflated tire. None of it is sold in metric, though...all in standard...ie. 1/2in, 3/4in, 1in, etc