Mount just about anything to your fence posts with our Mounting Cap. Slips over most standard T Posts. Great for mounting Mailboxes, Birdfeeders, Birdhouses and more. Simply press the top of the T Post into the bottom of our Mounting Cap. Due to variations in T Post manufacturing, gluing may be desired if the fit is too loose. Some T Posts may need to be de-burred slightly if the fit is too tight. The top flat part is 3 inches square. The part that goes over the fence post is 1-7/8 inch long.