Actually it's not Pauls, it's mine. This lovely little bracket is however made by Pauls Components in the good old US of A. It takes the place of your normal headset top cap and allows you to fit stuff that would otherwise be cluttering your bars ... lights, GPS, computer, etc.
If you use a handlebar harness to hold your kit then the bracket is fantastic. I've always found that if I have a harness fitted (to the bike, not me) and put a light on the bars, the 2 things interfere with each other. Fitting a light to the bracket raises it out of the way and keeps it central on the bike, so a win win really. They're available in black if you don't like silver and come with a nice new stainless centre bolt. I haven't seen them available over here yet but it's easy enough to order one on line. This one came from Aspire Velo Tech http://www.aspirevelotech.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=PAUL_STEM-CAP-MOUNTS and cost $28 plus a couple of quid shipping ... worth it for the very exclusive, Pauls sticker it comes with!