Poly-Grate II grates allow trees to be planted deeper on city, plus protect tree roots from punishment of daily pedestrian traffic. Accommodate tree growth for yrs. To expand tree opening, just use saw blade to cut larger hole on-site. High-density, recycled-plastic surface never corrodes or needs painting. Average grate weighs about 40 lbs.light weight lets 1 worker install grate within mins. Each grate meets ADA (American with Disabilities Act) requirements, thanks to small grate openings that wont pose obstacles to individuals. Reinforced with UV. inhibitors to prevent fading, plus resists damage from road salt. Select from round, square, and other shapes, in a range of diameters. All come with tamper-resistant assembly bolts.