Most but not all of our GPS products come equipped with a VHF transmitters. These may or may not be part of the price for the GPS unit. The VHF transmitters are made to order on a custom basis along with the making of the GPS units. In this way we configure the device best suited for your use. Telemetry Solutions VHF transmitters have mortality signal with user specified mortality delay time. For 1 -3 gram VHF transmitters we purchase our transmitters from a different telemetry company.