25 Health

15 Health and 25 Health are Powerups in Quake that are named by how much they heal. 15 Health is small, dirty, and does not have a functional light. 25 Health on the other hand is larger and has a working light.

The 15 Health is referred to as a "rotten" box in the source code. All health boxes may be intended to be 25 Health, but over time some have lost their full power, thus why the dirty boxes only provide 15 Health.