This kit provides (4) 70mm 12.9 class bolts to replace the factory 10.9 class bolts that hold the differential in place. These bolts are 15% stronger and have a longer shoulder for additional strength. This kit is a must if you run the 4th diff mount, and is a common upgrade in high power applications.
These bolts allow the proper torque spec to help keep everything in place and allow the bolt to do a better job of not shearing. Easy to install.