You must replace your Air Filter when the Air Filter Button is illuminated.
Standard Grinding Ring Use (Radius Rings™ and FIRE Rings™): The Air Filter should be replaced every 4 Grinding Rings.
Sparx X-Grind Ring Use: The Air Filter should be replaced every 2 Grinding Rings. Refer to the Maintenance Section of the Sparx Operating Manual for more information.
To view the Sparx Operating Manual, visit sparxhockey.com/manual.
Keep that Air Clean.
Every 200 sharpenings, you'll need to replace your Air Filter.