Caterpillar-style premium aftermarket track-shoe bolt. Part reference 4I7538. Size/application: Bolt M16x1.5×46. Corresponding track nut reference: 5I6125. High-strength undercarriage fastener for the specified track-shoe assembly. Brand compatibility: Caterpillar and premium aftermarket systems built to the matching Caterpillar specification. Match thread, shank length and machine model before installation.