Keep the drain system free of leaves and debris with a trench drain grate in place. The polyamide grate features the COMBee design, a unique pattern similar to a honeycomb. This plastic grate, also known as a drain cover, has an open surface area of 44.95 sq. in. per meter and flow rate of 138 GPM. The grate is rated NDS Class B and is both ADA compliant and heel proof. Use two 1/2 meter (19.69 in.) grates to cover one BG-FILCOTEN 100 4 in. trench drain.