Aquastar offers two different cover options for the 32'' Channel Drains. Our flush design, the 32CDFLxxx, is best used when the drain cover is installed where swimmers are active. Its flush design helps prevent toe stubbing and pool cleaner hang-ups. Our anti-vortex design, the 32CDAVxxx, is best used in shallow water, such as catch basins, and in pools that may experience more debris. Large amounts of debris, such as leaves, can gather and cover the openings of our flush covers, the slightly raised design of the anti-vortex drain helps prevent this.