This tool for injecting dye into R-134a car A/C systems works exactly as it's designed. It uses disposable dye cartidges that are threaded on both end with caps. When you are attaching the plunger and coupler hose, be aware that large end is sealed inside with the piston, but the small end will spill if it isn't held upright when you attach the coupler hose. I was very happy to see that the plunger assembly is entirely made of metal. It only has rubber covers on it.Not sure where it's made, there's no marking I can see. It's a well made injector, though.