Follow link for discussion of hydralic switch with silicone fluid. http://mgaguru.com/mgtech/electric/et119a.htm Follow link for this swith which spe if it's that it can be used with silicone fluid and operates on low pressure of 20 to 50 psi Gerry http://www.ronfrancis.com/prodinfo.asp?number=SW-32 Sent from Samsung tablet