Rant Bang Ur Mid bb kits work great but at a price that’s less than most. They come in a variety of colors to update your crankset. Click HERE for available colors and sizes. The Rant Bang Ur BB kit includes 2 precision R12 sealed bearings, 2 CNC machined 6061 aluminum cone spacers for a clean look, an aluminum internal spacer, 4 steel crank arm spacers for dialing in your chain alignment. R12 Sealed bearings. 100% CNC 6061-T6 alloy cones. Include spacers for a custom fit. Weight: 5.5 oz. If you aren’t sure if this MID bb kit will work with your frame, send us a message by clicking HERE with your frame make, model, and aprox year it was manufactured, and we should be able to confirm it for you.