Replacement ION 12 Black Heel Turret Assembly. If you need hardware for a pair of bindings, then purchase a quantity of two.
I had to buy two replacement turrets for two issues:
1. The orange **** gradually vibrated out of one of the bindings. It was just over a year old, so no warranty or compensation from G3 (Skied on about 15 days)
2. The binding adjustment "stickers" peeling off of my bindings, which made the tension adjustment impossible. G3 should etch the tension settings onto the bindings - and not use a flimsy plastic template.