The Dual Head is looks and feels just like the Presta Only Head, except for Schrader you unscrew the presta head and voila! use it for Schrader valves. Very Clever!
Plastic pump head is too brittle and broke while trying to pull of tube valve. Get the metal one instead.
The plastic head can shatter if stepped on; that is my only gripe about the design. Otherwise, the brass and rubber bits are pretty good. I ended upgrading the whole assembly with a brass head from a 3rd party manufacturer. Its a pretty decent replacement for the dual head air chuck that came with my floor pump.
I replace the original brass head, years ago, with this head for the convenience of also being able to pump up my kids tires with the Schrader head and the Presta head for my road bike. Ive never had a problem.
I used this as only a presta pump for a year without incident. Then first time I removed the presta portion to use it on a schrader valve, a very, very tiny red gasket inside the brass swivel part blew out when I was removing it from the inflated schrader valve and the entire unit is now useless.
I am completely disgusted with this pump head. The washer is far too tight and it is much more effective at releasing the air from your tires than putting more in. DO NOT waste your money here...