Bit shackle the connecting plate mounted on the turntable bushing drive pin hole. 13.9/16 in the four corners of the inner hole connected to the bit shackle. Apply to MPCH, MSPC, MDSP, MSP models pin drive wheel bushing, etc. The Number 1816 is suitable for the 23-49.1/2 in wheel bushing; Number 1815 is suitable for the 20.1/2-22.1/2 wheel bushing.