Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Would not work with regular "Schrader" valves

Before use, the tip of this pump must be configured for one of 2 types of bicycle tire valves, the Presta valve or the Schrader valve. The Schrader valve is used on many ordinary, everyday bicycles and it is just like the valve on an automobile tire. Like the reviewers above, I tried to assemble the pump but ended up having to call the manufacturer's customer service center to discover that parts were missing. The parts were sent and I assembled the pump as directed with customer service on the line. The pump is useless for Schrader valves. The metal collar of the pump tip is just narrow enough that it keeps it from fitting properly over the top of the valve stem and will not allow it to go deeply enough to push in the pin and allow air into the tire. As if that is not bad enough, it doesn't want to let go of the valve stem either and I nearly broke both the pump and valve getting it off. Maybe it works in Presta valves, I don't know.