You are buying 1 (ONE) NEW 5/8" DIAMETER by 18" LONG TUBE of CLEAR EXTRUDED ACRYLIC. (Five Eighths inch outside diameter by Eighteen inch long) These tubes have a 1/16" thick wall which provides an outside dimension (OD) of 5/8" and an inside dimension (ID) of 1/2". You are buying and will receive ONE 5/8" OD x 1/2" ID x 18" tube. To assure that you get the finest quality, the protective sleeve is kept in place on the rods while being cut to protect the acrylic. All tubes have saw cut edges on both ends. Please allow a tolerance of +/- 1/16" on all pieces.