Harvia IPX6 Waterproof Bluetooth Speaker

A speaker that's actually rated for the job: IPX6 waterproof, heat-resistant to 65°C, with an 1800mAh battery good for around 8 hours and USB charging. Bluetooth from your phone outside; music inside the heat.

Note: designed for sauna conditions up to 65°C — position away from the heater and ceiling in hotter traditional saunas.