"Used this adapter to fill tires with Schrader valves with my CO2 Presta valve device. Works great." Customer review - 28 January 2017
Schrader-to-Presta (Silver): This adapter converts Schrader valves to Presta so they can be inflated with a Presta pump.
How it works: As you thread this converter onto a Schrader valve, an internal brass bar depresses the Schrader valve stem allowing air to be pumped into the tire through the Schrader valve. The converter has a one-way valve that allows air to be pumped into the tire but prevents it from escaping when it's attached to the Schrader valve. When you remove the converter, the Schrader valve stem returns to its sealed position. (Thanks and a hat tip to Ed Cunniffe for suggesting this explanation).
