Related Clues:
- Limit, as a salary
- Put limits on
- Graduation flier
- Tube top?
- With "and" and 40-Across, emissions-reducing method whose first word (this answer) can follow the start of the answers to starred clues
- Pitcher's topper
- Baseball players' toppers
- Type of hat
- Soft flat hat
- Beer-bottle topper
- They may be locked on a computer
- Gas-tank topper
- Mushroom tops
- Baseball headwear
- Big letters, for short (and what your answers must be written in to understand the theme)