PEX-b refers to the grade of the PEX tubing, a reference to how the polyethylene turned into PEX. Viega PEX is an example of PEX-b tubing. PEX-b tubing is made through a process called the Silane method. This uses a chemical agent to break the bonds and form a tight cross-linking across the polyethylene in order to make PEX.
Viega PEX and other PEX Tubing for PEX Plumbing can be found at www.supplyhouse.com
