Clamps onto horizontal railings up to 2 INes thick. Easy to use hand knob makes installation easy. Extened arm hangs feeder away from railing to keep it clean. Feeder in picture is sold separately (HIATT38005). Attached to 1.5 IN thick board, overall 32.6 INes high, 20.2 IN reach, 1.5 IN wide. 2.6 LBs. Powder coat finish, verde vein green.