These windsock ball bearing extended frames are a rugged design constructed of a welded steel construction and then a powder coated finish for corrosion protection. They incorporate the same high quality construction as our standard ball bearing frames with the added performance of an extended frame. They incorporate a two bearing pivoting design for effortless pivoting. These frames are ready to be mounted on a 3/4" female pipe thread for the 13" and 18" frames. Use 1" female pipe thread for mounting the 24" and 36" frames.