Made of high quality steel material, for use. Expand the copper pipe to make the two copper pipes interconnected when the air conditioner is installed. It needs to be installed on hand electric drill. Size: 1/2mm - 12.7mm 1/4mm - 6.35mm 3/4mm - 19.05mm 3/8mm - 9.25mm 5/8mm - 15.87mm 7/8mm - 22.22mm color:Black Material:steel Package Contents: 6 x Tube Pipe Expander Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.