Oil way hydraulic system is of built-in structure to avoid damages during the collision, safe and reliable. Hydraulic dual ram BOPBOP Model: FZ28-21Main technical parameters:Bore:7 1/16" (279.4mm)Range of ram size:blind ram2 7/8", 3 1/2", 4 1/2", 5", 5 1/2", 7", 5"-5 1/2"adapter ram shear ramDimensions: 2120×764×573(mm)