http://www.jbr-plastics.com/plexiglass-acrylic-tube/ Clear Cast Acrylic Tube Clear Cast Acrylic Round Tube Clear cast acrylic tube is made of polycarbonate, which is easily worked, resists grease, oil, detergent, and most inorganic acids, and has a very high impact resistance at nearly 30 times that of safety glass. It has high elasticity for resistance to creep. It has an operating temperature range of -275 to +250 degrees F and a Rockwell Hardness rating of R 73-78. And the clear cast acrylic tube is suitable for applications subject to high impact or repeated use. Clear Cast Acrylic Square Tube