If you're looking at this you probably know this unit is literally the combination of the classic RCA OP6 preamp circuit with the OP7 mixer section on the front end. Its one of the greatest mic preamps of all time with an option to mix multiple channels or have a master volume control on the output. These have sooo much gain it comes in handy. It includes one modern XLR to large Canon style connector for the unit and an XLR output pigtail. I can add additional input adapters for extra. Let me know if you have any questions and please check out my other vintage audio gear.