high pressure tube fittings?

hi guys,

i've picked up some second hand rims and tyres for my roadie
and they come with a different fitting than i'm used to.

theres a small locking 'nut' which locks the valve in..
but my 'standard' bike pump i use for my MTB is larger etc.

what am i looking at here? previous owner said they were
'high pressure fittings'... tires indicate to fill too 100psi

the wheels and tires are wonderfully light, as opposed to old steel ones

am i likely to be able to get tubes in the standard fitting,
same as on my MTB?

cheers,

kim