Stainless Steel Counterweight Shaft for Astronomical Telescope Counterweight shaft with a diameter of 20mm, with 12mm and 16mm threads at both ends. It is compatible with equatorial mounts with 16mm and 20mm mounting holes such as SAGTI, XYG TI, HEQ5, EQ6 - R, EQ3, EXOS - 1, EXOS - 2, CGEM, AVX, 80EQ, 80DX, as well as Celestron PS and AM series products. However, it cannot be used for large star fields and AZGTI. If you need to configure it for other equatorial mounts, please measure before purchasing. Special note: This counterweight shaft can be used as an extension shaft for SAGTI/XYG TI counterweight shafts.