Rainbow was a prototype motorcycle built in 1950, by a gentleman of that name.
The machine was a form of step-through fitted with a 99cc Villiers two-speed engine unit that went under a cover. It had a tubular frame, light girder forks and a 20-inch rear wheel to keep the saddle height down, while the front wheel was a 26-inch bicycle-type. It was also fitted with legshields.
Although the machine was well made, it failed to go into production.