If you have an antique Olympia disc music box which was made by F G Otto and Sons in Jersey City, NJ and it is missing the coin operated mechanism, then you need these parts. Probably one of the only set of these floating around in the universe. These are only for the Olympia disc boxes which had the large spring motor in them, not the earlier Criterions with the undersized spring motors (some late Criterions did have the large spring motor as well The smaller Criterion motors have main gears off of the spring barrel the same size as on a Capital cuff box). Normally these Olympia coin op disc music boxes had a push lever sticking out the front of the box, which pushed the coin when it was in the hopper of this (if it was a slug with a hole, it wouldn't trip).I have used this as a pattern for years, but now it is time for it to find a new home. Good luck & thanks for looking!