YD-2 SLF Aluminum Big Bore Shock Set (Blue) Y2-SBBSBLSuper Low Friction Aluminum Big Bore Shock Set for YD 2. The cylinder diameter is wider than the conventional shock, and the shock length is newly designed for drift. As an on load shock, the maximum capacity has been increased to increase the sense of stability. The cylinder also uses a kashima coat treatment to achieve as smooth operation as possible, absorbing the slight vibrations common in resin tires and leading to increased traction.