Cannondale SRM compatible low profile PressFit BB30 Bottom Bracket Kit Kit includes two custom aluminum bearing shells/cups, two KR047/ steel bearings preinstalled, two black Cannondale alloy bearing shields, two FSA brass/rubber bearing shields, one wave washer, and one FSA 0.5mm shim. (Only use one set of bearing shields when installing.) This low profile kit is required to use an SRM powermeter on many PressFit frames including the first generation SuperSix EVO to get sufficient clearance. The aluminum cups have a lower profile than the standard plastic shell providing the needed clearance for your SRM. This is also an upgrade kit from standard nylon PressFit cup/bearing systems.