ustomize your catch basin inlet/outlet elevations with the 12 in. Square Catch Basin Drain Kit. Use with a 12 in. square catch basin drain grate to drain heavy flows from a variety of surfaces including lawns, landscaped areas, and patios. Kit includes an adjustable outlet catch basin with 2 open sides and 2 open outlet slides. Slides fit into catch basin sides and opening can be adjusted to accept pipe at your choice of three different elevations. Fits 3 in., 4 in., 6 in., and 8 in. drain pipes using appropriate outlet adapters (sold separately). The catch basin features a built-in basin sump area that’s easy to access and clean. Basin is made of polypropylene (PP) and slides are made of high-impact polystyrene (HIPS), treated with UV inhibitors.