Walkie-Talkie

Most of us think of the walkie-talkie as a smallish handheld device, but the original version had to be carried around in a backpack. (It weighed 35 pounds.) Designated the SCR-300, the Motorola-built, voice-only FM device worked in the 40MHz to 48MHz range and had a range of 2 to 3 miles. The first models reached soldiers in the field in 1943.

FM radios, known for the clarity of their signals, were a godsend to U.S. forces. Raines cites the praise of a radio operator serving in an infantry battalion: "FM saved lives and won battles because it speeded our communications and enabled us to move more quickly than the Germans, who had to depend on AM."