Fits on any sized deck or fence railing from 1" To 4" Wide; PLEASE MEASURE your railing to make sure it is no more than 4" wide! Works on chain link, wrought iron, composite, and standard wooden rails Planter arms are adjustable and lower stabilizing foot keeps planter perfectly level, regardless of fit Fits on any sized deck or fence railing from 1" To 4" Wide; Please measure your railing to make sure it's 1" to 4" wide. Hidden tray separates plants from reservoir; with slits to allow only the roots to reach the water reservoir below; avoiding root rot