This adapter shaft is the mainstay of the Switch Kick system. You therefore need to have this to be able to mount the many different beater head types.
If you have already bought the Switch Kick Two Way bass beater (starter kit), you already have the adapter shaft and thus do not need to buy it separately.
Switch Kick is a different type of bass drum beater. On the Switch Kick system, you can change the beater head itself in a few seconds, which also opens up the possibility of adapting your bass drum sound to the individual track you play - just like you do with your drumsticks, rods and whiskers.
There are a number of different beater heads for the system - all with the aim of giving you different tonal possibilities.
It is easy to change the beater with Switch Kick - so easy in fact, that it can be done in under 5 seconds!
In the video below you can see Jared Falk from Drumeo demonstrating the Switch Kick system.