RTS Mini-spool's are constructed from a high quality billet steel and deliver equal power and traction to both left and right-side rear wheels. The mini spool replaces the original spider gears in an open carrier differential, locking together both axles for even power to both rear wheels! Spool solutions are less expensive than lockers and weigh much less. Suitable for all 28 spline, 4 pinion Borg Warner 78 series differentials, including: EB2, ED, EF, EL, AU Ford Falcon VN, VP, VR, VS Holden Commodore VL Turbo & V8 Holden Commodore VT V6 Holden Commodore R31 For Nissan Skyline RTS offers a full line of mini spools in the most popular applications for differential modifications.