Catch basin gutter dowpout, that captures water typically into an underground pipe that carries water away from a building. This design allows for extremely heavy rai to overflow onto the ground / surface. Normal rai are typically handled by the drain pipe. There are two veio, a sloped bottom and a flat bottom. You need to print the basin box itself, the lidGrate and the pipeOutlet. Optionally print the corrugatedPipeAdapter IF your buried line is black corrugated pipe. The corrugatedPipeAdapter has holes on the top for a set-screw to hold in place, if needed. I have built and tested these, they work great for my needs.