Covert-Wireless CCTV Cameras
From the TV series ARROW

ARROW props delivered a few box-style mylar capacitors and some CMOS inspection camera heads (4.5 & 5.8mm types) to our workshop.

We were instructed to cut down the camera heads (only ⅜" was used) and install them into a through-hole to be drilled into each capacitor. 

Initially, we'd left the two pins of the capacitor intact as they looked like dual antennas, but this was laster rejected in favor of a cleaner look.

To add a little detail, a small cap-screw was installed to suggest that it served as a combination battery chamber cap and power switch.

Finishing simply required the manufacture and installation of small round plastic caps to cover the hole at the back and the application of slate-grey paint.
Picture
Shown prior to paint application, with the "antennas" still intact.
As seen in the TV series ARROW.