The Thelma Biotel 7.3 mm Acoustic Transmitter was originally designed for use with salmon smolt and is perfectly suited for small species where size is a limiting factor. The transmitter is suited for both manual tracking and automatic monitoring. The 7.3 mm transmitter has enabled researchers to study the migration of wild Atlantic salmon smolt down to 13.5 cm in length and for periods, sometimes up to one year of tag lifetime. It can be delivered both as Continuous Pingers and as ID Transmitters. The customer specifies pulse delay or coded ID, type of encoding, transmitting frequency, and the average delay for ID transmitters. The tags are compatible with our receivers and can operate on standard code sets (69 kHz) used by other equipment producers.