Using Bluetoothbluetooth 5.0 Audio Receiver With 3.5mm 4-way

BT receiver BC35 Wideway AUX - BOROFONE - Fashionable Mobile Accessories

GTEK 3.5mm 4 Pole TRRS audio cable - JB Hi-Fi

5 Pack 3.5mm Male To Male Coupler Extension Cable Joiner 1/8 Inch Trs Stereo Audio Wire Adapter Jack Plug Connector For Bluetooth Receiver Aux-in Cord

OQIMAX Aux Bluetooth Adapter for Car, 2 in 1 Bluetooth Transmitter Receiver for Hands-Free Call, Noise Cancelling 3.5mm AUX Bluetooth 5.0 Receiver for Home Stereo System/Headphones/Easy Connect - Yahoo Shopping

Bluetooth 5.0 Receiver Adapter USB + 3.5mm Jack Stereo Audio For Car AUX Speaker

3.7v-4v Bluetooth 3.0 Audio Receiver Module 1.8BT

Thought I'd share my solution to using my Bluetooth headphones with my Portal. Some of the earlier 3.5mm transmitters posted had poor battery life (4-5 hrs). Enter the Avantree Relay premium Bluetooth