You've found a vintage West Bend Lazy Day slow cooker lid knob (part P-291-19) for brown enamelware pot 5225. This West Bend slow cooker knob is black plastic with a metal / aluminum ring. This crockpot knob has some very tiny chips on the edges but is crack-free. It fits a slow cooker like the one in the 3rd photo; the spacer is not included.

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