This listing is for a Bel Canto DAC 3.7MK2 with VBL linear power supply. There are actually 2 VBL PSUs in this unit so if you have another Bel Canto compatible piece of equipment you can power them both with this PSU. It was a VBS and Bel Canto upgraded to 2 VBLs. The DAC portion was also upgraded from DAC 3.5VB to 3.7mk2. Identical under the hood to a original factory 3.7. Sound is unbelievable! Also includes the VBRef umbilical cord upgrade which is a $500 cable. I have the original packaging for the units. Please let me know if you have any questions. Thanks!