Refrigerant Gauge. eBay's robot won't allow us to list the refrigerant types for this as they deem it some sort of EPA banned refrigerant (go figure), so msg us and we can tell you what it works with if you can't see it on the image. Clear face measures about 2-5/8" side to side, chrome bezel measures about 3-3/4" side to side. Untested, used, sold for parts or repair. No return.