Get this X-Sense HFS07 Smart Smoke Detector Kit for only $161.99 (reg. $179.99) at X-Sense. You save 10% off when you use the promo code XSENSE10 at checkout. Plus, this item ships free. We could not find a better price for this smoke detector online. The X-Sense HFS07 Smart Smoke Detector Kit features 24/7 fire safety protection, instant app notifications, and pair multiple smoke detectors with base. Sales tax is charged in most states. Deal may expire soon.