This transparent black borosilicate tubing is sold by the piece, 20lb case, and 50lb case. The tubing is four foot in length with an approximate outer diameter of 25mm (1"). The transparent black color is not a heavily saturated color like the regular black. Each piece of tubing weighs approximately 1.6lbs. A 20lb case comes with about 12 pieces, and a 50lb case comes with about 31 pieces.