The success of Gillette's invention was largely a result of his having been awarded a contract to supply the American troops in World War I with double-edge safety razors as part of their standard field kits (delivering a total of 3.5 million razors and 32 million blades for them).
In direct response to Wilkinson's Bonded cartridge, during the following year Gillette introduced the twin-blade Trac II.
They claimed that research showed the tandem action of the two blades to give a closer shave than a single blade, because of a hysteresis effect.
This uses narrow blades stored in an injector device with which they are inserted directly into the razor.
The injector blade was the first to depart from the rectangular dimensions shared by the wedge, standard single-edge, and double-edge blades.
Shortly thereafter, Gillette modified the Good News construction to add an aloe strip above the razor, resulting in the Good News Plus.
The purported benefit of the aloe strip is to ease any discomfort felt on the face while shaving.
The injector, itself, was also the first device intended to reduce the risk of injury from handling blades.
The Gillette blade dispenser released in 1947 had the same purpose.
Blades for them are still being manufactured both for shaving and technical purposes.