How many times have you walked in to a trial room nonchalantly, totally unaware that a lecherous idiot is watching you from the other side, courtesy a “two-way” mirror installed? Follow these simple tests to tell whether the mirror in front of you is a normal one or a “peek-a-boo” session:

Peer through the glass

Try blocking as much light as possible as you peer through the mirror. If you see it leading to another room, then you’re in for trouble!

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Shine a light

Try turning off all the lights in the room and use your phone to flash a light onto the mirror. If it’s a two-way mirror, the other side would be illuminated. 


Tap the mirror

Tap on the surface of the mirror with your knuckle. It should produce a flat sound (because it’s placed on a wall). A two-way mirror, on the other hand, would produce a hollow sound because of the open space on the other side. 

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The fingernail test

Though not always accurate, you could perform a fingernail test to ascertain the presence/absence of a two-way mirror. Place the tip of your fingernail against the mirror’s reflective surface. If there’s no gap between your finger and the reflection; chances are, someone’s playing “peek-a-boo” with you. 

Mao Mao Pet