... Grade: ST52,ST52.3,CK45,E355,16Mn,STKM13C,SAE1020 Hydraulic Cylinder Honed Tube/Honed Tube/Burnished Tube Grade: ST 52,ST52 ... (Ra): < 0.8 MicronType: BK+S,high precision cold drawn,seamless honed,burnishedHigh precision cold drawn tube(ready to honed tube ...