Hope Press Fit 41mm bottom bracket in black is an external bottom bracket that has two bearing options: Stainless steel or ceramic and it's compatible with all common systems such as Shimano, RaceFace and Truvativ (An extra conversion kit is required for Truvativ). Like every Hope product, these cups have been CNC machined from a solid billet of 2014 T6 aluminium alloy to offer up some serious durability and strength characteristics. These cups will hold either the stainless steel or ceramic bearings from INA, therefore they're both replaceable and upgrade-able making these press fit bottom brackets a versatile component to add to your bike. Hope have employed the use of a non-contact, free running labyrinth seal to protect the bearing from the elements and the center tube is machined and seals the unit from any water that gets into the frame (who knows how the water always gets in!?) with some beefy internal O-rings. This press fit bottom bracket is compatible with 68mm & 73mm shell widths as well as being available in a 83mm width version and a road-specific unit.