Schmidt 635M Single BLUE Refill for Swarovski Pen with Plastic 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.