TRM Sensors has replaced the older TRM Remote Alarm Type-RO with the significantly improved TRM-Wall-Alarm.
The new alarm 
incorporates a loud (95 dB) Sonalert with an illuminated SILENCE push-button and two SPDT (Form-C) output relays.
The new Wall Alarm can operate in three different modes:
Mode 1: Traditional Remote Alarm : In this mode the power and switching are provided by a monitoring device (e.g. TRM-Easy5-Realy-U). When power to the Alarm is switched on by the control panel device, the buzzer sounds, the red push-button is illuminated and the two output relays switch to their alarm positions. The operator can SILENCE the buzzer but the pushbutton illumination and the relays are latched in the alarm state until the cause of the alarm is corrected.
Mode 2: Primary Monitor for up to four TRM-ALOS optical sensors. In this mode, the Wall Alarm is always powered and sounds the alarm whenever one of the daisy chained optical sensors detects liquid. No other equipment is required. Simply connect the sensor(s) and power to the TRM-Wall-Alarm and the system is complete.
Mode 3: Low cost, free standing monitor for up to four TRM-DFS-3 indoor fuel sensors: This configuration is perhaps the least expensive method to monitor up to four of the EPA tested, NWGLDE listed, TRM-DFS-3 diesel fuel sensors. It’s a great package for a simple tank or generator leak detection system consisting of one DFS-3 sensor and the Wall Alarm for under $600
Each Alarm unit comes with a covered knockout for 1/2″ conduit and an optional-use 5 Vdc plug-in power supply. The unit can also operate on 12 Vdc or 24 Vdc provided from a nearby control panel. A 3-hole cable grip is include as well.