Stax SRM-006t driver unit for pro and normal bias Stax headphones. It's versatile as it has 2 pro and 1 normal bias outputs. This one is configured for North America voltage, so no need for any step up/down transformers. Stock tubes are included, but installed are upgrade RCA tubes. Stock power cable and Stax branded RCA cables are included, but includes a 5ft upgrade Connex power cable (12AWG, Oyaide -made in Japan connectors). Also includes a set of 3pin XLR connectors for balanced setups.