RealDefense publishes Windows security software, including SUPERAntiSpyware. SUPERAntiSpyware scans a PC for spyware, adware, and other unwanted programs and can remove what it finds. Paid editions add real-time blocking and scheduled scans on top of the on-demand scan.
RealDefense also owns other consumer tools, including iolo System Mechanic. Those are separate products with separate licenses. A SUPERAntiSpyware subscription does not include System Mechanic, and a tune-up program does not include this scanner. The download is for Windows.
The on-demand scan can be the first step, and the paid edition is what continues to watch the PC after that scan. Definitions update while the license is active. The product page states whether the edition runs next to another antivirus or is meant to complement it.