The decals are 125mm in diameter and fix to the outside of your windscreen or rear window. They'll let fellow members see that you're "one of us" as well as promoting the forum to others.
You can place a secure order for one (or two!) by clicking on the PayMate button to the right. You'll be asked for your credit card details and a delivery address.
Please tell me your username in the Order No. section.
The cost is $6 per decal.