1 Piece - Battery holder holds 10 AA batteries with a 2.1 connector

1 Piece - adapter 5.5

comes with a connector on the end of the wires which is 2.1 this is a very common size 

if you use 1.5 NON Rechargeable batteries it will output 15v 

if you use 1.2v Rechargeable batteries this will output 12v