The 554s, like the 500s, was the wall version of the 500 set. It contains the exact same innards as the desk set 500 set. The 500 type phones were the first Western Electric telephone widely distributed in color. 15 original colors were produced.
Those colors included: black, ivory, dark blue, aqua blue, dark beige, light beige, dark gray, light gray, brown, red, yellow, green, white, pink, and turquoise. Custom colors, like lime and orange were also produced for special customers.
Besides Western Electric, other companies, like Kellogg ITT and Stromberg Carlson were licensed to produce similar sets. Produced over the span of 3 decades, the 500 type is probably the most common rotary dial telephone in the United States.