I ordered two and they arrived today. One had a broken gearbox, literally snapped in half. BUT the reason for ordering was the left thread screw. Its different to the others I have, but do fit. They have a star shaped screw thingy instead of a cross head. BUT the biggest problem is the head itself is smaller and doesn't lock the hex nut in place. I've got a washer that just seems to do the job, but I'm not convinced for the long haul. Going to take them apart tonight and salvage the other bits.