GREEN Single Schmidt 635M Medium Nib Ballpoint Refill that comes with a Plastic Cap Refill HOLDER. This is a Schmidt MINE (mini) model number 635 M (for Medium writing nib) BALLPOINT Ink Refill. The Schmidt Company is one of the best (if not THE best) manufacturers of refills in the business. NOTE: Private Reserve is a distributor for SCHMIDT and some of the refills we ship could be stamped either "Schmidt" or "Private Reserve" on the barrel.