There's no chrome, so assuming boom era, this would make it the bottom of the line Corsa model. Derailleurs and shifters appear to have been upgrasded form the original Simplex along with saddle and possibly seat post.

As previously stated, hi-tensile steel frame. Balilla or Universal center brakes, Gnutti steel hubs and steel rims, cottered steel crankset would be original. About the only OEM aluminum you'll find would be the stem and bars.

Atala was Italy's largest bicycle manufacturer during the boom and produced a full range of lighweight models from the entry level Corsa ($95 US circa 1973) to the top line Record Professional ($385 US circa 1973). Atala competed directly with other full line Italian manufacturers such as Bianchi, Bottechia, Chiorda, Fiorelli and Legnano. While they were well respected during the boom, like most European brands there were often lapses in quality, so things like paint and brazing may leave something to be desired, particularly if you are familiar with Japanese boom era models. Most European brands during this period sold primarily on their heritage and ride, which was typically more resilent than Japanese models. The Italians also put a little more emphasis on cosmetic design. Slightly upscale models like the Atala Gran Prix were real eye candy with lots of chrome and panelized paint schemes.