GTQ, Inc. Part Number: AQ201-NB and AQ202-NB GTO, Ine. narrow band receiver models AQ201-NB and AQ202-NB are designed to be used with all PROCTOR and Mighty Mule brand gate opener products together with your GTO and Mighty Mule narrow band transmitters. The narrow band transmitter can be identified by its color, gray. If you have an older model transmitter, or another brand, please contact our Customer Service Department at 800-543-4283.