These bulkplates are aerospace grade precision bulkplates made from 6061-T6 Aluminum bar stock on a 4 axis CNC and then professionally anodized.
1/4" x 3" Aluminum Bulkplate to fit fiberglass and cardboard 3" Coupler. Center hole is 1/4", outside holes are 1/4"-20 size and are 1.5" center-to-center distance apart. Price is for each Bulkplate.