This 2 ft. 6 in. x 4 in. dia. flagpole ground sleeve is made out of 1/4 inch PVC pipe. It is designed for in-ground residential flagpole installation. The PVC pipe inside diameter should be larger than the outside diameter of the flagpole. We recommend a 25 ft. flagpole with a butt diameter of 2-1/2 in. to 3 in.