The "Cross-pin" differential for the Mini is a super heavy duty differential designed as a significant upgrade for reliability and strength to the stock units. Every bit as strong as the limited slip, it is made from the same billet steel. The design incorporates two differential pins at a "cross" to each other and four planetary gears. Twice as many as stock! Not only does it handle more power but more gears mean much smoother performance and much less tendency for torque steer!These differntials can be used in all models of transmissions from the first 850s up to the current 1380's with 5-speed A+ gearboxes.