A hydraulic cylinder with 12 piston rods in the body. Designed to suit the excavator use. One cylinder performs splitting work very efficiently(splitting force more than 640tons) One cycle of inserting-expanding-shrinking-pulling out the cylinder into a hole of 120cm deep takes 3 to 5 minutes only. Normally hard rock like granite (compressive strength 1,500 kgf/cm2, tensile strength 60 kgf/cm2) is spaced at 80-90 cm each.