... of Hydraulic Breakers and attachments .Our main products including DBK Series Hydraulic Breaker,Front Cylinder,Rear Cylinder,Middle Cylinder,Piston,Inner ... Bushing,Outer Bushing and so on.DBK 750 Hydraulic Breaker Middle Cylinder1.Raw Material:20 Crmo2.Hardness:HRC ... have any questions,pls feel free to contact me. DBK 750 Hydraulic Breaker Middle Cylinder