This is a wardrobe accessory featured in the Star Trek: The Next Generation episode 'Yesterday’s Enterprise' for wear by Starfleet officers and crewmen in the alternate reality created by the emergence of the U.S.S. Enterprise-C from a temporal anomaly. The item is a reflective silver colored vinyl belt with black vinyl trim that features a matching over the shoulder strap with two molded resin Starfleet emblem badges attached via Velcro at the waist. The badges are painted metallic gold with a minor amount of wear from time and storage conditions, there are multiple inscriptions on the inner lining indicating use by various actors.
UPDATE: Somebody wanted this item more than me and made me an offer that I accepted.
A couple of screen-caps are included for reference.