Perfect for highway and roadside applications, the 90?, 5/16" Corner Bolt from Telespar helps create a tight corner fit when attaching one piece of Telespar Telescopic Tubing inside another. The Corner Bolt works in conjuction with a standard jam nut and is available in three different sizes: small, medium, large. Small works with posts of up to 2" O.D. Medium works with posts of up to 2-1/2" O.D. Large works with posts of up to 3" O.D.