What is it? The Automatic Feed Spool (AFS™) is the technologically advanced line feed system found on Black & Decker string trimmer products such as the Grass Hog™, Trimmer/Edger, and the 12" Cordless Trimmer/Edger.  Using centrifugal force, the system monitors the amount of line being used and feeds more line automatically as the cutting line shortens. 
 
The AFS system provides three main benefits:

• You do not need to bump the trimmer on the ground or push a button to feed the line in the trimmer
• Because the line automatically feeds as needed, you can now enjoy non-stop trimming and edging
• With no bumping and less starting and stopping, there is less wear and tear on the trimmer