X-Sense Wireless Interconnected Combination Smoke And Carbon Monoxide, Pack Product Features 2-in-1 Protection: This combination detector protects against both smoke and carbon monoxide Wireless Interconnection: When one alarm sounds, all alarms will go off 10-Year Sealed Battery: This wireless alarm features a 10-year lithium battery and will give a low battery warning Test/Silence Button: The single push of a button will either test or silence all units in the system Full Home Coverage: Link up to 24 Link+ wireless smoke alarms, CO alarms, and combination alarms for maximum home protection Easy to Install: This smoke and CO detector is easy to mount onto any wall or ceiling using the included accessories Shipping: Shipping is complimentary within the lower 48 US States. We Do Not Ship to PO/APO Boxes, HI or Alaska We Do Not Ship Outside of the Continental US All items ship within 24-72 hours of Payment For large items that require Freight shipping a valid phone number is required to call and schedule your delivery Terms of Sale and Feedback: Feedback is extremely important to us and If you are satisfied with our transaction, please take a moment to leave Positive Feedback. YOUR Satisfaction is our #1 Priority! If there are any issues, PLEASE contact us BEFORE leaving a neutral or negative rating so that we may resolve any concerns. We PROMISE we can make you happy if you give us a fair chance. Returns / Concerns: All items qualify for returns within 14 - 30 days of receipt. Buyer is responsible for return shipping on any item that is not damaged Please be sure this is an item you want before making your purchase. Customer Satisfaction is our TOP priority! All items are IN STOCK at time of listing. Inventory changes constantly and it is impossible to maintain a perfectly accurate count of all items. Please do not penalize us if we have to issue you a refund! Thank You For Your Business!