SwissStop's Full FlashPro Yellow King Brake Pads and Holders improve upon the first-generation Flash version by their use of deeper asymmetrical grooves in the pad block and a more pronounced leading edge profile. The idea is to "squeegee" away more water to improve the wet weather performance and the deeper grooves also help give the pads better modulation. They increased the total pad depth with more material above the wear line -- good news for the carbon rim user as they generally wear pads quicker than alloy rims. So for those using Shimano/SRAM brakes, FlashPro Yellow King pads are the finest that we offer. In fact, Mavic selects SwissStop pads as original equipment for their top-of-the-line Carbone Ultimate wheelset.The Yellow King pad compound is specifically made for use with carbon fiber rims. They provide unparalleled stopping power in both wet and dry conditions. They give you high durability, quiet braking, and perhaps best of all, excellent stopping power with aluminum rims as well. SwissStop makes it clear that there's no need to swap out pads from carbon-specific to non if you switch wheels from your carbon race-day gems to your aluminum training set. However, we'd recommend always checking your pads and removing aluminum debris before installing your carbon racing wheels. Any metal flakes embedded in the pads could be disastrous for your composite rims! SwissStop Full FlashPro Yellow King brake pads and holders come as a pair. The holders are CNC machined aluminum by TRP to SwissStop specifications. They are ready to bolt right onto your brake caliper. One order gets you 2 pads total -- enough for one wheel.