We bought what we thought was the right size. 22 inch blinds for a 22 1/2 inch opening. Wrong, need to buy 23 inches. We learned our lesson. We had trouble putting it up because of this, we ended up putting the brackets on the top of the frame, not the sides. 3 out of 4 stays up without a problem. It's not the fault of the blinds, it's the fault of the buyer (me) for not understanding how to measure mini blinds. The installers (my sons, a rocket scientist and a bio-medical engineer) discussed, googled, etc and made it work.