The CD Upgrade kit is good for 25 CDs and comes with 25 blue rings and includes 25 large CD-sized transparent discs. Each of these large transparent discs fully covers the label side of the CD while the blue ring is mounted on the shiny data side of the CD. Simply apply and listen, a tremendous upgrade.
"So now comes the question of how much improvement over a non-'upgraded' fully naked disc to a fully CD Upgraded version is there? Well I was dumbfounded. . These kits come with items that are specifically made for improving CDs. No hocus pocus here folks. No false scientific claims. Refreshing, it seems to improve the way the digital bits sound when decoded."
– Steven R. Rochlin, Enjoythemusic.com