Carry tape

Peephole Reverse Viewer

The Tactical Door Viewer (about $90) was developed with the help of the law enforcement industry to help them assess potential hazards behind dwelling doors.

This peephole reverse viewer is simple to use and can be carried in your pocket for use anytime.

The officer places the reverse viewer over the peephole in the door and can look into the dwelling without alerting anyone inside.

Found at bookofjoe.