Upgrade your VELUX roof window with this original replacement blackout roller blind for M04. Enjoy near-total darkness and smooth manual operation. No tape measure is required to find the correct size; simply locate the window code reference at the top of your open VELUX roof window. This blind is compatible with VELUX roof windows with reference codes: GGL M04, GGU M04, GHL M04, GHU M04, GPU M04, GIL MK34, and GIU MK34. It's an inexpensive option from VELUX, ideal for replacing old and worn blinds. The blind is manually operated with stepless positioning, offering an almost complete blackout effect. Installation is easy as it's tailored for VELUX roof windows for a perfect fit, and can be installed in minutes with the pre-fitted mounting system. If your mounting brackets aren't pre-fitted, you will need to purchase the Z0Z 230 separately.