how do I wire a 240 duplex into 4 wire romex??

Okay I'm almost done with my electrical work but I cannot figure out how to wire 10 gauge 4 wire romex into a 240 duplex plug.. can somebody please give me some help.. there are brass screws on each side instead of silver on the other side.. help please. This dual duplex plug is to plug in both of my 1000 watt ballasts..

Red to brass, black to brass, bare copper to green ground screw. White/common wire is not used, fire it up and let me know how it grows!

The red and black go on opposite sides of the outlet. Tightly snug screws and don't just mash it into the box, try to pre bend the wires in a Z shape so the just fold into the box. Think of an accordion or scissor lift. Hope this helps