Tom, I'm not certain if the wiper arm that came off my S1 is original or not but dimensionally, if appears to be very close if not identical to my S2 arm. The only difference being the blade length. The S2 blade w/o the refill is about 11.5" long, the S2 blade is approx. 16" long. If that's the case a standard length wiper arm should work. The knurling on my S1 arm is stripped, will look at a S2 arm for replacement.