A Bluetooth transmitter with features to reduce the likelihood of unwitting loss includes a first housing, a second housing, a circuit board, and a button. The second housing couples to the first housing. A side of the second housing opposite to the first housing defines at least one groove for connecting to another housing or a holder. The circuit board is secured in the second housing. The button couples to the first housing and connects to the circuit board through the first housing. The button is configured to initiate a Bluetooth signal transmission.