This component is needed to mount a light or other accessories that use a picatinny rail on your Glock. I use this on my Glock gen.3 Is necessary a screw M4x30 and a nut. I suggest the material ASA or ABS.

For position of part you can see the photo. Infill 80% or more Brim support grid 20% Layer 0,2 with nozzle 0,4 mm