Year of the Cat, and not to plug the clip, but a damn near identical live version of the song, except the weak and truncated sax solo. The item in question starts at about 3:03 in- is it the Armwatch by Mobus? Groovy arm jewel? And is it glued on, or safety pinned through his skin?
He’s wearing a button with the logo for the Old Grey Whistle Test, the show that they were appearing on. Compare the badge at 3:12 with the backdrop at 4:09. At around 3:06 or so you can make out the strap or tape they used to hold it on.