The stock foot stirrup on the Matryx is weak and can trap your foot.
The Pin'd Angled Stirrup
Thru-bolt Holes - Won't pull aluminum threads like stock and other stirrups. Provides massive strength improvement while keeping the same 3-position adjustability.
Sweeping Angle - creates stronger geometry while giving your foot a chance to escape in a bad situation and still provides all the toe grip utility you could want.
Uses provided high-strength nut and bolt for each hole (x4).