Dimart 20mm x 20mm Threaded Square Tubing Tube Insert Caps Covers 40 Pcs 20mm x 20mm Threaded Square Tubing Tube Insert Caps Covers 40 Pcs Top Size : 20x 20mm / 0.7" x 0.7" (L*W) Bottom Inner Size : 13 x 13mm / 0.5" x 0.5" (L*W);Over Height : 25mm /1" Material : Plastic Color : Black Package Content : 40 x Square Threded Inserts