Edwards Signaling 720 series low cost, non adjustable bell which may be operated off of a 590 transformer or DC power. Universal economy bell widely used in homes, apartment houses, plants, OEMs. Especially suitable for AC powered security systems with battery standby. For office installation, see Cat. No. 13 Series Bells or Cat. No. 15 Series and Cat. No. 115 Series buzzers. For combination bell and buzzer see Cat. No. 730 Dixie Buzabel.