DKL P10 Velux Blackout Blind - Old Type *** Group 1 Colours ***Finding the right size blind is easy and you don't need a tape measure or a ruler. Simply open your roof window and look for the code located on a silver plate at the top of the window. The genuine original VELUX blackout blind is ideal for bedrooms or any room where you want to completely block out the daylight. The blind is of the highest quality