Safety razor the second blade cuts it further. The extent to which this is of practical consequence has, however, been questioned. Gillette introduced the first triple-blade cartridge razor, the Mach3, in 1998, and later upgraded the Sensor cartridge to the Sensor3 by adding a third blade. Schick/Wilkinson responded to the Mach3 with the Quattro, the first four-blade cartridge razor. These innovations are marketed with the message that they help consumers achieve the best shave as easily as possible. Another impetus for the sale of multiple-blade cartridges is that they have high profit margins. With manufacturers frequently updating their shaving systems, consumers can
Safety razor with its "Gem" models. Although these brands of single-edge razors are no longer in production, they are readily available in antique trade, and compatible modern designs are being made. Blades for them are still being manufactured both for shaving and technical purposes. A second popular single-edge design is the "Injector" razor developed and placed on the market by Schick Razors in the 1920s. This uses narrow blades stored in an injector device with which they are inserted directly into the razor, so that the user never needs to handle the blade. The injector blade was the first to depart from