Socket x Spigot. 150 psi working pressure (tested to 500 psi static @ 73°F). Made with high-impact PVC Type II Cell Class 15344-C. One piece cylinder - no solvent weld to leak. Meets/exceeds ASTM and ANSI standards. Molded in the USA by KBI. Internal high quality self-lubricating EPDM o-ring for long life and smooth movement. NSF Standard 61 listed.