It looks to me like a magnetic bracelet. From what I heard, it helps with circulation and joint pain, which is very useful if you're a full-time guitarist like Mr. Tipton here.
While we are missing most of the true Sinful Gals, I have a request. Who has a close-up or can identify Glenn's wristband? Just cruising through old pix myself and it looks to be one of those "harmony / balance" suckers. Any help?