Description The Nittan Ceilingwall Mounted EV-SDR Sounder is a small, low-profile device that can be mounted on the ceiling or wall. It has 12 tones (3 approved), and can be selected easily via DIP switches. Mounted Sounder 12 Tones Features: Nittan Evolution FSK Protocol Addressed EEPROM (Programmer). Select 3 Approved Tones from 12 Tones of DIP Switch This Sounder replaces the EV-ABS Sounder Not for use with Detector