Its the HD aux kit, along with the HD signal relocation kit.

Trimming the plexi is easy. I drew an arc with a sharpie, drilled a series of small holes over the line, and used a dremel to cut between the holes.

 

You can also use a jigsaw and a fine tooth blade to cut the shields. That's how I took 2" off the top and then trimmed to bottom to fit tightly around my 7" Fatboy headlight. Since I'm not as precise as I'd like I cleaned up any little irregularities with a sanding drum in the dremel.

 

She looks sharp, been thinking of adding the same set up. The first time that I saw it was on a XL1200 Low. I was surprised how good it looked on a Sporty; looks even better on a Dyna!

 

Here's how it look on my FXD 2003: