For choosing watches with steel bracelets, what is the difference between lite w/ tool and regular bracelets
The normal one is steel all the way through, so heavier, but you can remove the pins by hand to adjust the length of the bracelet. The hollow one is lighter, with the trade off that you need to use a tool (included) to push the pins out and shorten the total length.
Edit: The full-steel one requires a screwdriver to adjust.