Small cylindrical very low light pinhole camera thats perfect for uses as a hidden camera.
1/4 " Sharp CCD Hidden Camera (0.05LUX , 420TVL) W/3.7mm Lens.

With the pinhole lens you can make this your ideal hidden camera by placing it in any item already in your environment,all it needs is a pinprick of a hole to see through, and the low light facility of this camera helps with that job too.
This cameras been used by companies to make their own hidden cameras for customers showing that it is a ideal hidden camera.