UL Listed,1 Million Cycles In Endurance Are Guaranteed, 5 Years Warrant. Universal Application, Designed For All Standard Installation. Power Size Range:1~5 In Various Coser Body. Two Separte Valves For Close & Latch Speed Adjustment. Optional Back Check Function. Optional Built-In HOLD Open type:501D,502D,503D High Quality Hydraulic Fluid, Low Freezing-point,Door Closer Operates Smoothly Form Temperature Of -30℃ To 40℃.