Tom, just email me a copy of the receipt and I will send you one. We actually get those check valves from a US manufacturer, they are generally pretty reliable, there is an issue with the basic design that can lead to them clogging and jamming open but it has no easy solution. Momentarily the pressure on each side of the valve is equal and it does not close fast enough, if the check valve is not suspended above the bottle, it is highly likely powder will back up and jam the valve, but this is easily remedied by flushing it out with a syringe and a piece of airline tubing, if really caked up you can use vinegar and let it sit for a while. The innards are stainless and nitrile rubber.
