2" without maker's name and with noticeable dark small spots around 80% of the outer edge but the area within the text remains totally clean. Reads "Brand-Rex/Way Ahead In Wire And Cable." Text references a company which during the 1970s ran a series of advertisements using Buck Rogers in two magazines titled Electrical World and Electronics. Our thanks Buck Rogers expert Gene Seger for this information. Button may have been distributed only at an industrial trade show, thus accounting for its extreme rarity. Only example known to us.