Details of pressure in 2 seconds (5)
I believe the answer is:
specs
'details' is the definition.
(short for specifications)
'pressure in 2 seconds' is the wordplay.
'pressure' becomes 'p' (abbreviation).
'in' means one lot of letters goes inside another.
'e seconds' becomes 'secs' ('sec' can be a synonym of 'second'. I am not sure about the '2' bit.).
'p' inserted into 'secs' is 'SPECS'.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for specs that I've seen before include "Glasses (sl.)" , "provider of focus" , "Glasses (abbrev.)" , "Instructions" , "you can see right through them" .)