Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: Bad presta inflation

I had problems getting the presta valve head to depress the inner stem so it would take air on my road bike. I messed around with it for a while trying to insert it right and finally gave up and returned it. I ended up buying a Specialized pump with a dual valve head and it works better.The actual build quality of the pump is better than some because the floor plate is metal and the pump doesn't flex when you pump high pressure, but beware of the presta head.