Prevents "dang my chain came off" when down shifting to the Granny ring. Install the Granny Guard and loosen the front derailleur inner stop screw until it permits shifting under pressure. Now, go ahead --- shift right in the middle of that climb. You won't over shift. Gone are the days of struggling up a hill in the middle ring because you underestimated how steep it was and are afraid to downshift in the middle of the climb.
Works on most recumbents.
Works with 24t to 32t 74mm Bolt Circle Diameter (BCD) chainrings with a 5 bolt pattern.
Center to center measurement of adjacent holes on a 74mm chainring is 43.5mm
Includes 16mm chainring bolts and 3.5mm chainring spacers, which work with many stock granny chainrings.