ARB 4X4 Accessories Air Locking Dana 44 Differential, Front 35 Spline (3.92+) RD109 For Use With 35 Spline After Market Axles;For Use With 3.92 And Up Gears;Air Activated Selectable Locker; Converts From Open Differential To fully Locked Or Spool; Simple Push Button Operation; Requires Air Compressor Sold Separately ARB 4x4 Accessories ARB Dana 44 Super 35 Spline 3.92 Ratio Up Air Locking Differential - RD109 RD109 Differentials