Frost was a motorcycle produced circa 1920, by Romney Frost of Wolverhampton.
The engine-design of this machine was most unusual as it was a flat-twin tandem with normal opposed cylinders plus a further cylinder added at the end of each. The engine unit was very complex and was to be offered to other firms, but only one was made and fitted to a machine.
While testing the motorcycle, Frost fell off and broke his leg and nothing further was heard of his design. It is thought that this may have been due to very high costs of production.