Material: Made of bearing steel. It has uniform high hardness and wear resistance and high yield strength. Pressing Tool: A product of the pressing process with this tool making its way into the line set of HVAC systems. Function: When the air conditioning is installed, expand the copper pipe, create a mutual connection of two copper pipes. (To be installed on a hand electric drill.) EASY TO INSTALL - Perfect for installers no matter if you are learning or doing. Multi- size: 7 or 8", 3 or 4", 5 or 8", 1 or 2", 3 or 8", 1 or 4", 6 different sizes per set for your choice to meet your needs. Specifications: Material: Bearing Steel Color: Black Stem Type: 7mm Triangular Shaft Size (approx.): 7 or 8" (22.2 mm or 0.87 inch), 3 or 4" (19 mm or 0.75 inch), 5 or 8" (15.9 mm or 0.63 inch) , 1 or 2" (12.7 mm or 0.50) inch), 3 or 8" (9.5 mm or 0.5 mm or 0.5 mm or 0.5" 0.37 inch), 1 or 4" (6.3 mm or 0.25 inch) Height (approx.): 1 or 4", 3 or 8", 1 or 2", 5 or 8", 3 or 4", 7 or 8" 1 or 4": 4.5cm 3 or 8": 4.5cm 1 or 2": 5cm 5 or 8": 5cm 3 or 4": 5.5cm 7 or 8": 5.5cm