Okay, dumb question time again!!

Looking to get a 20kg servo for the lifter.

http://www.ebay.co.uk/itm/Power-HD-4...gAAOSwTglYlokr

two questions.

I know they plug directly into the receiver, but the description mentions torque with the amount of volts. So do these servos need a direct supply from the battery as well?!

AND if so, if I want to run a 3s system will this be too much for the servo only stated at 6.6volts..!?!?!

Thank you again!