Meet the drain grate, the guardian of your drainage system. Place on top of the catch basin drain, riser, or low-profile adapter, and it defends drain pipes by blocking potential intruders such as dirt, leaves, and debris. The 12 in. Square Catch Basin Drain Grate, also known as a drain cover, is ideal for draining heavy flows from lawns, landscaped areas, under downspouts, patios and walkways. Made of high-density polyethylene (HDPE) treated with UV inhibitors.