Iso Rivolta began before World War 2 Isothermos as a manufacturer of refrigeration units. Post war however, they joined numerous other Italian companies in mobilising the masses.
Iso’s first vehicles were small capacity motorcycles and some basic looking scooters, but in 1958 they launched their new 150 scooter (also to be their last), which blended the style of both Milanese rivals Lambretta and Piaggio’s Vespa, resulting in a rather tasty looking machine.
With a 2-stroke, 4-speed engine and a claimed top speed of 50mph, it’s 3.50×10 wheels were the same size as the best Lambrettas and Vespas of the day and it’s spec comparable, so you can only presume that Iso simply weren’t big enough to take on Innocenti or Piaggio at this stage – or that they’d rather concentrate on the bubble-cars they also produced at that stage.
By the way, known as the Iso Milano in the UK, this is assumed to be a mistake made at the time by someone reading the manufacturer’s badge complete with city of origin and coming up with an incorrect assumption.