Heavy Duty Axle for the Savage XS and Bullet trucks! These Heavy Duty parts will reduce drivetrain wear and extend service intervals.[section 2]Other Heavy Duty Parts also available for the Savage XS and Bullet:#109921 - HD AXLE 5X40MM #109925 - HD GEAR SHAFT 5X29MM #109926 - DIFF SHAFT 5X23.5MMOther Heavy Duty Parts also available for the Savage XS only:#109922 - HD CUP JOINT 5X10X19MM #109923 - HD CUP JOINT 5X10X15MM