Direct to battery connection.
The box is a radio shack project box. It comes with a lid that screws into place. I made my own fuse block from one from Advance Auto that was originally for 6 fuses- cut it in half, and used it for my 3 relays (low beam, high beam, and my fog lights). Countersunk a set of nylon bolts to hold the relays in the bottom of the box and then bolted it down to the flat spot under the battery tray. Made a couple of notches where the headlamp wiring would run in/out and sealed it up. Works pretty nice. Got the idea from
http://www.danielsternlighting.com/