4in Square Pole Tenon Adapter 2 Horizontal 2-3/8in O.D. Tenon 90°

Features: 

For use with square, non-tapered steel and aluminum poles. Furnished with four 5/16" hex head stainless-steel bolts. Vertical tenon measures 2-3/8" O.D., and is made of steel tubing.

Fixtures mounted to this bracket can be adjusted both vertically and horizontally.