SupremeTech 12 x 18 x 0.04 Inch Acrylic See-Through Mirror, 12x18 Inch, Clear 

• 12 x 18 x 0.04 Inch Acrylic See-Through Mirror, Scratch Resistant, 40% Transparent. Can be used for a smart mirror, surveillance, or theatrical application. Shatter resistant, unlike glass. Slightly bendable.
• A two-way mirror is coated with a thin, almost-transparent layer of metal. The result is a mirrored surface that reflects some light and is penetrated by the rest. Light always passes equally in both directions. However, when one side is brightly lit and the other is dark, the darker side becomes difficult to see from the brightly lit side because it is masked by the brighter reflection of the lit side.
• 2nd photo monitor off. 3rd photo monitor on, bright room. 4th photo monitor on, dark room. 5th photo reflection of ceiling light. 6th photo ceiling light seen through mirror. 7th photo demonstrates nature of two way mirror.
• Be sure to remove thin protective film from both sides before use. Side with blue protective covering may have a 2nd clear protective covering underneath. Protection may be scratched, but underlying mirror should be unscratched. Blue covering is on reflective side, clear covering is on back of mirror.