How does Contra Vision Perforated Window Film work?

Building Wraps are a highly flexible media, so it is no surprise that they play a valuable role in major product launches, branding campaigns and high profile events.
In the age of viral communication, Building Wraps are reassuringly visible, dominating the local skyline and communicating your promotion to the wider community both outside and inside the building.
Contra Vision Perforated Window Films are the PERFECT media for this type of application.
Our products transform glass surfaces, enabling graphics and advertising messages to be visible from one side but not the other side, which remains see-through.
Product : Performance White on Black in 20% Transparency

[@madmark0]

need somthing like this that will show an image on a bit of card but can be moved off onto another bit of card easily and be see through. Any ideas?