I have the 54 arms and blades. I found that the last replacement glass wasn't flat and I got the concave side out so I have to use the 54 blades that work on a curved windshield. For blade replacement I use 22' rubber refills for 126 Mercedes (81-92) and cut them in half. They fit the cages just fine and wipe well. The spring tension is not what it ought to be though and if it's windy the blades float with little pressure holding them to the glass.
