You are buying 1 (ONE) NEW 4" DIAMETER by A NOMINAL 12" LONG TUBE of CLEAR EXTRUDED POLYCARBONATE. (Actual dimensions are Four inch outside diameter by 11 7/8" inch long) I CUSTOM CUT THIS FROM A NEW 8 FOOT LONG LENGTH OF TUBE. THE SAW BLADE IS 1/8" THICK. THEREFORE 1/8" OF MATERIAL IS LOST DURING THE CUTTING PROCESS. These tubes have a 1/8" thick wall which provides an outside diameter (OD) of 4" and an inside diameter (ID) of 3 3/4". Polycarbonate is 250 x more impact resistant than glass and 30 x more impact resistant than acrylic. It has more flex than acrylic when under lateral pressure, as seen in the photo. You are buying and will receive ONE 4" x NOMINAL 12" (11 7/8") CLEAR POLYCARBONATE tube. To assure that you get the finest quality, the protective sleeve is kept in place on the tube while being cut to protect the polycarbonate. All tubes have saw cut edges on both ends. Saw cutting can cause micro chips on the ends of the tube as seen in the pictures. Please allow a length tolerance of +/- 1/16" on all pieces and a ID/OD width tolerance of 0.020.