Convert any sealed mid or spanish bottom bracket to the DRS system.
What is DRS ? This is a system designed and patented by Vocal, it is a system that allows you to add drag to your cranks to stop them turning when you take your feet off, the system works with a simple plastic drag plate that runs on the outer face of the bearing. Which can be adjusted to suite the individual rider style, so no more searching for your pedals when you do a tail whip they will be exactly where you left them.
DRS System 3 screw adjustment, drag washer for non driver side.