Case of 6 Scentry III-GFRAB Battery Back-Ups Add a battery back-up to each Scentry II-GFRAB gas alarm sold separately with gas valve controller capability unit sold separately. Rechargeable battery keeps pilot lights lit during intermittent power failures as happens in many mountain states. Note if the alarm is sounding, the pilot light will not be lit. Replace a CCI Control automatic gas valve shut off with the Scentry III-GFRAB not included . This versatile gas detector senses explosive gases such as propane gas and natural gas and includes adding options such as battery back-up, remote gas sensors and low battery detection. 12V output gives the option of a phone dialer to alert owners of vacation homes, etc. when power has flickered or failed at their home. Up to 4 remote gas sensors can be added near gas ranges, gas water heaters, gas furnaces, gas heaters, etc. to add protection using only one gas valve controller Scentry III-BB Safety First Battery Back-Up Specifications Case ABS Plastic Physical Size 4.625 inches by 4.625 inches x 3.625 Inches Weight 4 lbs. per unit. Color Gray Pre-wired for fast installation Power 12V DC, 4.5 AHR This is a case of 6 battery back-up units. Made in USA Manufacturer Safety First USA, Inc. This item ships from a separate warehouse and may require extra time for delivery.