Specification ES-51 Stroke - 0.98" Cylinder Effective Area - 1.10"² Oil Capacity - 1.09"³ Collapsed Height - 4.33" Extended Height - 5.31" Collar Thread - 1 1/2"-16 Collar Thread Length - 1.10" Outside Diameter - 1.50" Piston Rod Diameter - 0.98" Piston Internal Thread - 3/4"-16 UNF Piston Thread Length - 0.63" Base Fix Holes Bolt Circle U - 0.98" Base Fix Holes Thread - 1/4"-20UNC Base Fix Holes Thread Depth - 0.55" Weight - 1 KG / 2.2 LBS Hardened and chromed piston increases durability and reduces wear Collar threads, piston threads and base mounting holes enable easy fixturing Heavy duty, straight pull return spring Eagle Pro Crossover Guide Eagle Pro Model: ES-51 Enerpac: RC-51 Simplex: R51 Power Team: C51C Williams: 6C05T01 Ram-Pac: N/A BVA: H0501