I purchased 5 sets of blackout blinds for a large bedroom window that fit in rails on the glass so need no tools to fit. The fitting system is ingenious but the results are poor. Whilst light does not get through the fabric it certainly does bleed through everywhere else. I thought I was purchasing the kind of system you have in a caravan where no light gets in but this is far from the case. Sadly I feel I have wasted my £375 and could have spent it more wisely elsewhere. We have plenty of other windows that need blackout blinds so I will find an alternative supplier.