The ARB Dana 70/80 Spline 4.10 Down Air Locking Differntial
 
Key Features 
For use with 32 Spline Axles 
For use with 4.10 Down Rations
Air Activated Selectable Locker
Convers from an Open Differential to a fully locked or spool
Easy Button Push Operation 
It Requires on Air Compressor - Sold Seperately