Rain Bird® DG12SFG 12" Green Plastic Square Flat Drain Grate is a rugged square grate designed to be used in conjunction with a catch basin. This grate is manufactured from a structurally foamed High Density Polyethylene (HDPE) with a UV inhibitor to reduce sun damage. This grate has large opening slots for maximum flow while still preventing large debris from entering the drainage system. Typical application would be areas where floating debris would block a flat grate. For safety reasons and to prevent vandalism or theft the grate has two holes enabling it to be screwed onto the basin.