Wireless doorbell offers a versatile tool to get your attention at the front door, back door or customer service area without the cost and hassle of getting a wired bell. Water-resistant, push-button ringer may be used outdoors or indoors and attaches easily with screws or foam tape (both included). Wireless receiver operates up to 250′ from the ringer and is easily hung on nail or hook (not included). A pleasant, ding-dong tone is one of 32 ring options. Ring tone can be changed by simply pushing a button on back of receiver. Ringer is paired by code with a chip inside the receiver so multiple doorbells in close proximity may be used, but only the desired receiver will sound. FCC certified doorbell operates on three AA batteries (sold separately) plus one 12V A23 battery (included).