Dr Solomon's Virex  6.1 & 7 for Macintosh 
The technology leader in Macintosh virus protection, delivering complete protection from both known and unknown viruses faster than any other product, with our patented SpeedScanª technology. With Scan-At-Download - a Virex exclusive - you are automatically protected from viruses in files downloaded from on-line services and the Internet. 

Other powerful features include scheduled scanning, extensive network protection, instant updating, native Power Macintosh support and compressed file scanning, including StuffIt, Compact Pro and ZIP archives. Virex is also optimized for compatibility, so it runs with applications and system extensions without conflicts. And it's Mac OS 8 savy! 

Virex 6.1 supports Mac OS 7.55, 8.x, 9.x .
Virex 7 supports only Mac OS X (10.3 or later) .