Hi-oh10/16/20 series are spring built-in hydraulic buffers, and are used at the bottom of the shaft, if the elevator gets out of order and slides down, it will take the decelerating effect, and the knockout rod will trigger the switch, and then the safety circuit is enabled. Oh-10: Rated speed: less than or equal to 1.0m/s Buffer weigh range: 300kg~2500kg Pillar gully routing(s): 100mm Free state (l): 388mm A*b (mm):150*90 A*b (mm):150*90 Diameter c (mm): 14 Hydraulic oil brand: hl-46 Oil is needed: 0.48l Oh-16: Rated speed: less than or equal to 1.6m/s Buffer weigh range: 700kg~5300kg Pillar gully routing(s): 175mm Free state (l): 625mm A*b (mm):210*100 A*b (mm):270*150 Diameter c (mm): 18 Hydraulic oil brand: hl-46 Oil is needed: 1.7l Oh-20 Rated speed: less than or equal to 2.0m/s Buffer weigh range: 1000kg~5300kg Pillar gully routing(s): 290mm Free state (l): 915mm A*b (mm):210*100 A*b (mm):270*160 Diameter c (mm): 18 Hydraulic oil brand: hl-46 Oil is needed: 2.6l