Retrofiting your telescope with a GOTO drive? Use our precision CNC cut round Ground Board for accuracy. Our Ground Boards feature Baltic Birch plywood, strong and very wear resistant as well as one foot having an internal mount for the Power Feed Through plug. Each comes with ball bearings at two positions and Teflon at the third (requires smooth laminate on the Rocker Box bottom). Smooth movement for lower torque and longer battery life. We can supply with three Teflon pads if you prefer to keep the textured (Ebony Star or Pebble Board) laminate on the Rocker Box. The sizes listed below are a guide, use the largest bearing radius that your rocker box will accommodate.