Circular aluminum plate is .25 inch thick and 18 inch diameter. Wonderful add-on for Excitron rotary tables. 8 .250 inch diameter holes are placed every 45 degrees around the outside of the rim, and there are mounting screw holes in the middle for attaching to the Excitron rotary table slots. Customizable placement and mounting options for additional cost. Plate can be anodized for additional cost. Contact us for details.