Can be a thoughtful gift for friends or family members who own a mixer Functions of Knobs: The 2 knobs are used for speed lever and locking lever, and it includes only black plastic knob, no levers or other parts, please refer to the photo Kitchenaid pro 600 610 Ksm Accolade 400 ksm 150 scv ksm150psob 150PSWH K45 Artisan 5qt 6qt How to replace it , The damaged plastic knob can be replaced without disassembling the machine, it is very easy to replace it by yourself Speed Control Knob Replacement Part Mixer Set of 2 Black Plastic OEM Quality Lock Lever Knob