SHM, for those unfamiliar, refers to Super High Material. I'm not a techie or audiophile, but here's what little I know. These CDs, manufactured in Japan, are supposedly made of a better (super high) material, that 'can result' in better sound. They can be played on pretty much any CD player.
Many go out of print, and fetch good $ on eBay. (Bowie being a good example).
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