Apollo PEX tubing is cross-linked, high density polyethylene. The silane method, also called the “moisture cure” method, results in PEX-B, where the cross-linking is performed in a secondary post-extrusion process, producing cross-links between a cross-linking agent. The process is accelerated with heat and moisture. The cross-linked bonds are formed through silanol condensation between two grafted vinyltrimethoxysilane (VTMS) units, connecting the polyethylene chains with C-C-Si-O-SiC-C bridges. PEX tubing is for use in hot and cold potable water distribution systems. PEX tubing can also be used in “continuously recirculating” plumbing systems up to 140 deg F while maintaining chlorine resistance. The tubing may be installed in concrete, gypsum based lightweight concrete, sand, asphalt, in or under wood flooring or behind wallboard or plaster.Tough and flexibleCopper tube size dimensions (CTS)Less expensive than other plumbing materials