If you are aware of all the brands and varieties of PEX tubing that are available, you may wonder whether there are any differences in the wall thicknesses, inside diameters, or outside diameters of the PEX. All standard PEX tubing sold at SupplyHouse.com of any particular size will be identical in these specifications (regardless of brand and the presence of an oxygen barrier). 1/2" PEX, for example, has a .475” inside diameter and a .625” outside diameter.
The only exception is PEX-AL-PEX tubing. PEX-AL-PEX contains an embedded layer of aluminum that thickens it slightly. It also has a larger inside diameter and outside diameter, making PEX-AL-PEX incompatible with standard PEX fittings. With PEX-AL-PEX, you must use either compression or Multipress fittings.
