Attwood SL36&nbsp;&ndash;&nbsp;50&nbsp;5&nbsp;Gas Spring Piston, 44&nbsp;cm People's gas springMade with oil used is marine grade, bio-degradable, you are in the plunger out of gas more environmentally friendly with the marine All pistons are the test ASTM B117, Attwood salt spray and of 30,000cycles of life The mounting brackets sold separately