HH12ZB250 Carrier Limit Switch, 3" 250 Degree Fahrenheit. Gasket Included. Replaces part number: HH12ZA251. This is a Carrier OEM part. If you need help verifying the correct part for your equipment please call our office and we will assist you. 1-855-431-2842. Shipping rates apply to the Continental US only. For Canada, Alaska and Hawaii additional shipping is required. Please call the office for a quote.