The Marshall Kilburn III measures 273 x 169 x 150 mm and weighs 2,800 g, giving it a sizeable but portable physical presence with a total volume of 6,920.55 cm³. It carries an IP54 rating, offering protection against dust ingress and water splashing from any direction, and is noted as sweat resistant — though it does not claim full waterproofing. The unit includes a detachable cable and features a control panel placed directly on the device, making adjustments straightforward without needing a separate remote, which is not included. It does not feature a touch screen, RGB lighting, or a neodymium magnet, and no travel bag is bundled in the box. The warranty period covers one year from purchase.
The Marshall Kilburn III uses stereo speakers with a combined audio output of 2 x 36W, covering a frequency range from 50 Hz up to 20,000 Hz. The sound pressure level is rated at 50 dB/mW. It does not include a subwoofer or a passive radiator, and there is no magnetic shielding. The speaker has no built-in microphones, meaning it does not support hands-free calling or voice input.
The Marshall Kilburn III is equipped with a built-in rechargeable battery offering up to 50 hours of playback on a single charge, with a full charge taking approximately 3 hours. A battery level indicator lets users monitor remaining power without guesswork. The battery is not removable, and the speaker does not support wireless charging, so recharging requires a wired connection.
The Marshall Kilburn III connects wirelessly via Bluetooth 5.3 with a maximum range of 10 m and supports multipoint pairing with up to two devices simultaneously. For audio codecs, it is compatible with AAC and supports Auracast broadcasting, while aptX in all its variants (including aptX HD, aptX Adaptive, aptX Lossless, and aptX Low Latency), LDAC, and Bluetooth LE Audio are not supported. A single USB Type-C port is present, though there is no 3.5 mm headset socket, AUX input, 3.5 mm male connector, or external memory slot. The speaker does not support Wi-Fi, Ethernet, AirPlay, Chromecast, DLNA, or NFC pairing, and there is no microphone input available.
The Marshall Kilburn III can be used wirelessly and supports control via a remote smartphone, giving users flexibility in how they manage playback. It includes voice prompts for audio feedback and a sleep timer for scheduled shutoff. Fast pairing is not available, and the speaker does not support voice commands or built-in radio. It cannot function as a power bank to charge other devices.
The Marshall Kilburn III does not support stereo pairing, meaning it cannot be paired with a second unit to create a two-speaker stereo configuration.
