5 blade shaving surface technology - has 5 blades spaced closer together to help reduce pressure with less irritation and more comfort than Mach3. 1 precision trimmer blade - built into the back of the cartridge. Perfect for tricky places like sideburns, under the nose, and around facial hair. All Fusion cartridges can be used with all Fusion razors. Comments? 1-800-Gillette. www.Gillette.com. www.pg.com. Gillette. The best a man can get. Patents: www.pg.com/patents.