Soft copper tubes  8–42 mm,  3/8–1 5/8", Wall thickness ≦ 1.5 mm. Soft aluminum tubes, soft precision steel tubes  8–42 mm,  3/8–1 5/8", Wall thickness ≦ 1.2 mm. Soft stainless steel tubes  8–42 mm,  3/8–1 5/8", Wall thickness ≦ 1 mm. Proven quality tool for expanding and calibrating tubes. REMS Ex-Press Cu –for making sockets yourself. 6-face mandrel for even and concentric expanding. Extra long sockets according to DVGW. Expander heads with calibration neck, fit other makes as well.