Steel M series mono posts are designed for new home construction and can be easily installed by 1 person in less than 15 minutes. M series monoposts are fully assembled, have no loose parts, and are coated with corrosion-resistant primer. 3" outside diamater, 11-gauge carbon steel tubing. M series mono posts have a 4-1/4" x 7-1/2" x 3-gauge welded plate on 1 end and a 4" x 5-1/2" x 3-gauge swivel plate on the adjustable end. Each column has a 4" adjustment range.