A Cellular Phone is a wireless telephone that can be small enough to carry in a pocket. Most cellular phones can be set up in a vehicle in such a way as to permit use of the device without having to lift or hold the handset to one's ear. Some models make it possible to dial a number stored in the telephone's memory by using only the user's voice. The telephone's signal range de-pends on the location and on the service provider, who usually has a map displaying the effective service area. A cellular phone is a convenient method of conducting private conversations; and the cost of using it is dependent upon the amount of use.