This Limited Edition Silver Foil enhanced box was the $15k stretch goal in the Assassincon Kickstarter and is limited to 1000 copies.
From Kickstarter Update #4:
"Limited Edition Box! With Silver Foil *
Only 1,000 of these Limited Edition foil boxes will EVER be made. Snipe it while you can! The Limited Edition box will be sleek matte black with silver foil overlay on the AssassinCon logos.
- Limit 1 Limited Edition box per backer."