A ring with a camera in it to take pictures of suspects at a party.
There is little more to add.
Positioning a ring to take photos will be a lot more difficult than using this handy device... A Spy Cap with built in hidden video recorder that can be paired with your phone to dial/pick calls hands free. Its dimensions and weight are similar to caps sold in any shop. This is mainly due to the extremely small pinhole lens camera which is hidden within a rivet in the hat. So even if people are looking directly at the cap, they won't notice anything! The shop below stocks many other types of spy camera.
Again, not the most sophisticated piece of tech, but at less than £30 it is a real introduction into the World of Spies. The police probably wouldn't use something as rudimentary to bug someone, but you could
At less than £5 you would not expect much, but this car style key ring provides 8gb of photo and video recording time. The colour video is in AVI format. It is the smallest pin hole camera made for spy use. A driver is not required to use it as a storage device