Made of the finest cross-linked polyethylene (PEX). Flexibility that allows fast installation, bends easily around corners. Withstands freezing, gets stronger as the temperature gets colder. Tubing has been tested to withstand freezing down to -95 deg. F. Winterizes easily - can be used with most anti-freeze solutions. Repairs easily, should ever a frozen tube need thawing, simply apply heat, using a heat gun, the flexible tubing will not weaken from the applied heat. Type A PEX. Maximum working pressure: 160 psi (pounds per square inch at 73.4 F (degree Fahrenheit), 100 psi at 180 F, 80 psi at 200 F.