What is 2 way mirror - they can see you, but you can't see them

Mirror illusion in Hotels or showrooms(Trial rooms) -
HOW TO KNOW 2 WAY MIRROR OR NOT????
What is 2 way mirror - they can see you, but you can't see them

Place the tip of your fingernail against the reflective surface and if there is a GAP between your fingernail and the image of the nail, then it is a GENUINE mirror. H...owever, if you...r fingernail DIRECTLY TOUCHES the image of your nail, then BEWARE, IT IS A 2-WAY MIRROR! (There is someone seeing you from the other side). So remember, every time you see a mirror, do the "fingernail test."
The reason there is a gap on a real mirror, is because the silver is on the back of the mirror UNDER the glass. Whereas with a two-way mirror, the silver is on the surface.

So guys & girls be careful....hv a try someday who knows u may cought somebody who is cheating u.....