Simple FPV plug.

thingiverse

I remember making those small adjustments with Makerware, saving the file and ending up with a longer .thing file. Usually, that one is right on depth, although your mileage may vary. This design provides an easy way to seal off the body when deciding not to mount an FPV camera. Be aware that inserting it fully isn't intended for locking it in place; rather, those nibs are meant to crush or deform so you get a snug fit going through the hole. Insert until the barrel end meets the inside of the body's edge. Fill the space between the "brim" and the underside of the cap with some super glue drops - not too much though! This secures the cap, preventing it from shooting off during high-impact collisions that might force it into wires or electronic components. With superglue holding it firmly in place, the design remains easily removable even after solid impacts, leaving room for future upgrades should you decide to take a new direction. The model can be printed at various settings, so don't stress over this part! For optimal results print it using the 100% infill and two outer walls with a layer thickness of .20 millimeters in PLA. Print them any way you'd like as long as it gets done successfully!