3 Pieces Plastic Fish Tank Isolation Divider Filter Grid Plate Patition Board Aquarium Net Divider Holder Segregation Board with 3 Pcs Sucker/Black Easy to snap fish tank isolation divider filter grid plate together: 1. Grid divider only snap together in one direction such that you have to alternate which way the face. 2. Look closely at the slight taper in the connections to see which way to insert them. TIP: If you can not get these grids to connect together, zip ties also. How Do You Wash It? Just rinse with hot then cold water no soap. 1.These are sized just right for standard 20 gallon long, 29 gallon and 55 gallon aquariums which are all about 12inches wide inside. 2.Two are just right for a 20g long, three are just right for a 29 gallon and three will work for a 55 gallon, but about 2 inches short of reaching the top, which you can make work with thick layer of gravel. 3.You will have to cut them to fit any other size aquarium. Each Fish Tank Divider can be snapped together to make a large panel, also can be cut easily with wire cutter to your desired size to fit your fish tank.