These are attachments for the FPV Camera Angle Protractor which can be found here:

https://www.printables.com/model/411229-fpv-camera-angle-protractor-print-in-place

You can slide off the sliding flat piece and replace it with one of these that is designed to grip on to the lens for accurate angle measurement and adjustment for the specific camera.

Current Cameras

• DJI FPV (Original Camera) + Caddx Nebula Pro (Same Lens)
• Caddx Nebula Nano Pro
• Runcam HDZero Nano 90