Toasters have evolved significantly since bread was first toasted over open fires. Early electric toasters in the 1900s had basic heating elements but issues with burning. The 1905 invention of the alloy nichrome allowed heating elements to reach high temperatures without damage. The first commercial electric toaster was created in 1909 by General Electric. In 1913, Lloyd and Hazel Copeman invented the "automatic toaster" that could flip bread without touching it. Charles Strite solved the burning problem with his 1919 invention of the pop-up toaster using springs and a variable timer. The introduction of pre-sliced bread in the late 1920s increased toaster usage in American households.