Black phosphate coating prevents rust and and helps to prolong tool life Available in 3 different sizes, 1/2 inch, 3/8 inch and 1/4 inch, you can choose according to your needs It is widely used in various equipment installation, factories, production lines, automobiles and various mechanical maintenance It is machined black heat-treated chromium steel with high strength, resistance and excellent durability The ball spring at the rod end and the anti falling bolt hole in the adapter can the plug in place to safe use and falling off, Manufacturer: PENCHEAK