The reverse peephole viewer can be used to look through from the outside of any standard peephole – and give you a 180-degree view of whatever lies on the other side.

It was originally designed for law enforcement, but now it seems that one can be had by any pervert of suitable means – and by suitable means I mean anyone who is able to purchase from Amazon and has more than $64 of credit available..

Without damaging the peephole or leaving any trace, you now can simply use this reverse viewer on one end of the peephole and then you can see the inside of the room, from the outside! This peephole viewer gives you at least 180 degrees angle of vision. It is easy to use and can be carried in your pocket for use at any time. This product is developed with the assistance of the law enforcement industry to help them assess potential hazards behind house doors. Highlights: 1. High quality lenses 2. Light weight 3. Easy to carry and use 4. Focus is adjustable (new function on March 13th,2012)

Got a peephole? You might want to build a cover for it, or at the very least cover it with a square of black tape.

Price: $64 [Source]