The Societa Italiana Auto Transformazione Accessori, or SIATA, was founded by Georgio Ambrosini and later assisted by his son Renato. Not unlike Abarth, SIATA was a tuning firm for Fiats. Breaking out on their own, SIATA produced cars basically using Fiat components, although USA engines from Chrysler and Crosley were also used.

SIATA made many great cars, but the Spring won't be remembered as one of them. SIATA produced approximately 3,500 Springs between 1968-70, producing as many as 13 per day at one point. The Spring was the biggest selling car that SIATA produced. The Spring was conceived by Renato Ambrosini as a last-ditch effort to inject the company with much-need cash. Using stock FIAT 850 sedan mechanicals and mounting a special body on a slightly modified (narrowed) FIAT 850 floorppan, the Spring was trying to recapture the success and looks of its own earlier mdoel,the SIATA Rallye.
The Rallye was an attempt to emulate the success of the MG TD. But alas, the Spring was a victim of its own success.

Selling in Italy and exporting to Germany, France and the US the Spring was oversold by anxious dealers who gladly accepted money down on the cars. The factory could not keep up with the demand - especially because of a 4 month strike, and with irate customers and dealers hounding SIATA at every turn, production ceased, ending a great little car company. Eventually the company ORSA acquired the rights to produce the SPRING under their nameplate and did so from 1973-1976, although I've never found evidence of this car - other than this possible picture here. It is estimated that maybe 10 percent of the orignial 3,500 Springs survive today.