I needed a custom beehive type drain cover to replace the flat cast metal cover on my outside basement well exit drain that kept getting clogged from leaves and tree debris. The cast piece sunken into the concrete has a flat section closing part of the drain opening for some reason. This cover allows for that detail. The cover has an outside diameter of 113mm to fit inside the rough cast piece properly. CAUTION: Tripping hazard!Print the two pieces, bond the top piece to the bottom piece to create the dome, and paint with a bright color as it is a tripping hazard. If I'm going to be using the basement exit constantly for some reason, then I'll remove it until I'm done, and then reinstall it.