Smart Solution for Smart People! Smart Film for Commercial and Residential Applications. Retrofit your existing glass – simply peel and stick! Its self-adhesive layer sticks to any existing glass without any special equipment.
How does this work?
Allows the light due to electric voltage to the crystal twisting molecules in it 90 degrees in between two polarized filters, WHEN voltage is present (on) , allows light to pass through. Without voltage (off), it blocks light.