When installing disc brakes on both the front and the rear, the standard master cylinder is no longer sufficient, the yield of these is too low, so you can build enough pressure in the brake system. This single acting hoofremcilinder has a cylinder diameter of 22.2 mm while this standard 17.46 or 19.05 mm depends what age, thus you build a higher pressure which is necessary for the 4 calipers. This B-grade cylinder has only one major difference with the A-grade and that the reservoir, which in the B-quality sound is a lot less and more quickly can cause problems with leakage but the price is therefore again. In terms hoofremcilinder there is no difference, so if you have a history of B-grade purchased you can still loose A-grade tank mount. Originally it is a bus master cylinder which is intended for bus bar but is commonly used Baja , s and Buggies in connection with the permanently mounted tank. You can easily master cylinder replaced in an existing brake discs regardless of whether or drum brakes. The following overview is also the A-grade also mentioned, if you click on it takes you to the page where the high yield cylinders are listed for double acting brake.4