This kit is a direct replacement for the standard rubber bushes that are normally used to hold the front of the differential in place on the chassis. 2 different variations of bush available for this particular application. These are Standard (STD) & Fast Road. SuperPro is a renowned manufacturer of polyurethane bushes for both the classic car and modern car markets. Before being manufactured each bush is put through vast amounts of testing in a variety of different environments to ensure that a quality product is produced. SuperPro bushes can be used for many different applications, these include standard road use, racing, rallying, hill climbs and also for off-road purposes.