They have an adjustment in them to maneuver the side a bit at the bottom when the blinds are half open to compensate for old windows in my 80 y

I purchased the 3812 size x 2 for my living room and i think they were made in a different factory because there are small differences and the shades are not adjustable horizontally as are the 37x66 in the bedroom

O building so the shades are straight across the bottom