This product is designed to block out 99% of the visible light, and can also serve to provide additional security. The material is 1.52m wide and you can purchase from 0.5m to 30m in length.
The film comes with an easy to follow set of instructions.
Please Note: If you require complete Blackout Film with no light bleed, please choose Black Blackout. White Blackout Film allows up to 1% light transmission, so might have to be doubled up to achieve 100% blacking out. For perfect results, you might have to add a bead of black/white silicone around the edge of the glass to completely stop the light from coming through.