Poly-Grate II is molded of 100% recycled post-industrial plastic resin. Will not rust, rot, or corrode. Never needs painting. Choose from round grates in 3-, 4-, and 5-ft. sizes; and square and square/round combo grates in 4- and 5-ft. sizes. Weighs less than 40 lbs. To accommodate tree growth, cut larger opening using standard saw blade on site. Extensions available for larger tree pits. Includes tamper-resistant hardware to join grates halves. Optional security hardware available.