12x12 Plastic NEO catch basin (NEO 300-CBP), downspout guard, A ClassVodaland's 12x12 plastic NEO catch basin is a cone shaped basin with a 12" width, length, and height. This catch basin comes with an 8" height plastic downspout guard. This grate is specially designed to collect rushing water from your downspout. The basin includes a pipe connection adapter available in diameters of 2 1 2 and 4 (see drawing for details). Alternately, you can use the connection cut outs on the side and bottom directly with various