USB B power cable with DC connector. This enables a USB DAC to be powered by a seperate power supply rather than taking the power from the USB host. With this comes a short 'data only' USB cable and a 'power' cable with a split feed.
I have been using these 3 cables to power my HRT USB DAC and Raspberry Pi with a single iFi iPower PSU with great results.
£22.00 for all 3 cables including UK postage.