Jack investing billions making device for skiers (1,3)
I believe the answer is:
t bar
'device for skiers' is the definition.
I can't judge whether this definition defines the answer.
'jack investing billions' is the wordplay.
'jack' becomes 'tar' (both are informal terms for sailor).
'investing' is an insertion indicator (inserted letters are taken in or invested).
'billions' becomes 'b' (abbreviation).
'tar' enclosing 'b' is 'T-BAR'.
'making' is the link.
Can you help me to learn more?
(Other definitions for t bar that I've seen before include "skiing guide?" , "beam" .)