Tube End Cap - TOOGOO(R) 20 Pcs Plastic Square Blanking End Caps Tube Inserts 25mm x 25mm Product Name : Square Tube Insert Top Size : 25 x 25mm / 1.0" x 1.0"(L*W) Bottom Size : 18 x 18mm / 0.7" x 0.7" (L*W) Over Height : 17mm / 0.7" Material : Plastic