Review on Blovess Yueton 10pcs Copper Presta to Schrader Converter: Car Valve Adapter for Bike Tube Pump & Air Compressor Tools by Russell Roberson

They work well as an adapter for Presta valved tires on a Schrader pump. Just remember to loosen the nut on the presta valve before using it. I don't know if it's absolutely necessary to retighten the presta valve if you leave the adapter on the tire. I would definitely use a valve cap if you leave it on the tire.