The KAX643ME has a twist connection. Therefore, the KM models need an adapter for this drum beater. More information on compatibility is available here:
https://www.kenwoodworld.com/de-de/kenwood-adapter
The low-speed connection on the front of the machine must have a connection with a hexagonal opening, not a slot. Then you don't need an adapter. Otherwise you need a "bar adaptor to twist", KAT002ME.