CertainTeed Corp. has expanded its line of Certa-Lok PVC well casing to include 41⁄2-inch and 5-inch diameter Integral Bell Well Casing in SDR26. Featuring a conventional belled-end joint, Integral Bell well casing is engineered to meet the requirements of ASTM F480 and is listed by NSF International as safe for use with potable water. The spline-locking design of Certa-Lok PVC well casing is designed to form a full-strength joint in all weather conditions and requires no solvent cement or reinforcement screw attachments. An elastomeric O-ring provides a pressure seal. CertainTeed Corp., Card No. 190