SPECIAL KIT FOR TREK BB90/95 FRAMES THAT HAVE "OVERSIZED" BEARING SOCKETS (Standard bearings fit too loosely). THE OUTSIDE DIAMETER OF THESE BEARINGS IS SLIGHTLY LARGER TO COMPENSATE FOR OVERSIZED BB BEARING SOCKETS. THE BEARINGS ARE "DEEP-GROOVE RADIAL" DESIGN. AS PICTURED: The blue silicone auxiliary seal is supplied for the non-drive side bearing and takes the place of the OE stainless steel end cap (or you can re-use your end cap instead of the seal we supply) See additional information/specifications below.