A MUST for setting pinion flange crush / bearing preload or just reinstallation. Doing a Ring and Pinion install or just replacing / upgrading your flange / yoke. Replacing that leaky pinion seal / gasket. Proper Installation & service of driveline parts is an often overlooked detail when servicing differentials, axles, etc. These items seem "tough", but are high precision, tight tolerance mechanical devices that require the utmost care to ensure longevity and max performance, particularly in race and off road environments. Massive produces these our driveline tools to maximize ease of install & ensure maximum accuracy. Holds pinion yoke or flange in place when removing or installing nut. These fasteners require GIANT torque values which can bend inferior tools easily. The Massive tool is fabricated from huge 3/8" thickness steel, CNC laser cut. We than zinc & yellow dichromate plate them for long lasting rust resistance (the other guys supply you with rusty uncoated stuff? WHY?). Created with 1/2" & 3/4" drive compatibility, as well as tang to allow common piece of 1-1.125" tube or pipe to be used as handle. PRO KIT 1/2"-20 grade 8 threaded Pinion Shaft Center Forcing Screw, Flange Holding tool, Puller Tool, Custom Molded Foam Interior Purple case, & Massive's BFB ( Big Freakin' Bar) with vinyl grip handle! BFB is 1.0625" .113" Wall 1018 Galvanized steel to support even the highest loads! 2.125" opening allows even the larger impact sockets clearance to pass through to the nut. Slots accommodate most popular yoke/flange patterns - compatible with the Ford 7.5, 8", 8.8, 9", 9.75, IRS & straight Dana / AMC / Jeep 20, 35, 44, 50, 60, 70, 80 Chrysler 7.25", 8.25", 8.75", 9.25". 1310 1330 1350 yoke. The GM 7.5, 8.5, 10.5, 11.5, 8.2, 9.25, 9.5, 10 bolt, 12 bolt, 14, bolt. Many Toyota 7.5 and 8". Fits many flanges / yokes - but of course not ALL, so please do your research or ASK to be sure before purchasing! THANX!