This Enerpac MZ-1004 extension tube is used with MS-series hydraulic cylinders using the A-16 lock pin (sold separately) and has a 5-ton capacity. It is 18" in length and has 1-1/4"-11-1/2 male National Pipe Thread Taper (NPT) connection on both ends.Enerpac manufactures high-pressure tools and equipment for industrial applications. The company, founded in 1910, is headquartered in Menomonee Falls, WI.