This is an eavestrough outlet for 2x3 inch downspout piping. I printed it with PETG so that it can withstand high heat from the sun over time.

There are no screw holes. I was able to screw into it just fine with metal screws used for installing downspouts and eavestroughs. I added a dollop of silicone to the flange portion to prevent any leaking around the downspout.

I've included the Fusion360 project export so that others may modify it if required.