ProPress® 20788 Tube Tee, 4 x 4 x 1/2 in Nominal, Press End Style, Copper, ImportProPress and ProPress XL (Copper) are safe, reliable and economical copper pipe installation systems that use modern cold press connection technology. Viega ProPress fittings are for use with type K, L and M hard copper tubing from 1 2 to 4 in and soft copper tubing in 1 2 to 1 1 4 in Dia. All tubing must comply with the ASTM B88 standard. ProPress fittings are approved for installations in both above and below ground applications. Per code, local