Sorry, I read the spec sheet for mine and kinda thought it would be on everyone else's as well.
It's in the motor. Looks like it's only Samsung as a quick google brings up things like "unique auto balancing spindle motor". AB8 - ball bearing auto balancing system that reduces disc vibration at high speeds, at bottom of this page.
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got hits for ABS(Auto ball Balancing System)and it may get called Auto Balancing Spindle Dunno if it's unique because they patented it but no one else uses it and a patent is only thing that would stop CD makers copying features from other makers. Can spin off an "application patent" years after the original expired, prevents anyone else using that invention for that specific use for 16 years. Old technology gets recycled into new.