KNOB TYPE: This Knob Is The Change Over Selector Switch Knob. MODEL NUMBERS: This Knob Is Compatible With Model Numbers ECP3120, ECP3420, ECP3220R INSTALLATION INSTRUCTIONS: This Knob Does Not Come With Installation Instructions! WHAT YOU GET: This Offering Is For ONE Chrome Change Over Selector Switch Knob! Don't See Your Model Number? Send A Message! This Change Over Selector Switch Knob is compatible with the following model numbers: ECP3120, ECP3420, ECP3220R Installation Instructions do NOT accompany this part! Don't see your model number? Send a message!