New concepts of design and economic efficiency emerged in Europe, as well as in the independent market in the US, in the 1920s, which combined all components of the telephone in one desk-top unit.
The base was supported by four felt- or leather-covered triangular feet attached under each corner to prevent scratching furniture surfaces.
The housing sat atop the base, secured with screws, and contained the rotary dial and a handset cradle.
The housing was originally cast from a zinc alloy until production sets were increasingly made from a thermoplastic material, Tenite, by 1941.
[5] Requests for custom colors could also be fulfilled, including the traditional dark gold, statuary bronze, old brass, and oxidized silver hues.
Beginning in August 1955 and extending into the 1960s, the Bell System remanufactured the 302 as the type 5302 in its distribution center work shops, with a newly designed housing and eventually with the G-type handset of the 500-type telephone, which gave the set a similar appearance to the 500.
Conversion kits using a 302-style housing and F1 handset to replace older manual candlestick telephones with an external subset were available.