Different valve stem designs

[Bmwbig6@xxxxxxx]

Does anyone know where I can get those small stubby metal valve stems that 
collapse back into the wheel when not in use?  (I think they're 
spring-loaded)  How are these different from the ones used on Fikse or BBS 
racing wheels (which just seem to be really stubby but not extendable).  Any 
comments on advantages of each over the conventional rubber ones?

Ben Trapp
"Rondell Princess"
'90 535iM (sharked, of course)

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