Flushable transmitter for use with any receiver that operates at 512 Hz, such as Prototek’s FR-1, LF2000, LF2100 or LF2200. Not compatible with the AR-1 receiver. Locate in cast iron or nonmetallic lines and tanks. Continuous tone only. Simple push button on/off, LED shows you it is operating and when the battery is low. 4 hour battery life, shelf life 12 months. Range is over 8 feet in cast iron, 12 feet in nonmetallic lines.