If you have decided to to remove the firing pin blocks in your CZ 75B style gun, there are two ways to fill the gap left by removing the lifter from the sear cage "ejector".
1/ is to replace the lifter with this spacer.
2/ would be to replace the B Sear (Smaller one) with a PRE B Sear (Larger One).
This part replaces the firing pin lifter, and fills the gap in the sear cage.
The lifter needs to be removed to shorten the Single Action (SA) reset on the trigger, just removing the blocks from the slide lightens the trigger but does not alter the SA reset.