There are several radically different mechanical designs of preselector gearbox. This was coupled through a fluid flywheel to an epicyclic preselector 4-speed gear box. The gearbox was a four-speed preselector type unit. The preselector, consisting of three coaxial cavities, attenuates all RF signals outside the receiving band. Some 1950s-era James motorcycles were built using Villiers engines and a preselector gearbox. The Riley's ENV preselector gearbox provided easy progress through the gears. The transmission was either a four speed manual or optional preselector gearbox. The integrated device is "both" a preamplifier and a preselector, and either name is correct. Preselector gearboxes faded away as modern automatic transmissions took their place. A Daimler four-speed preselector gearbox with "fluid flywheel" was used. The transmission used a 5-speed Wilson preselector gearbox with a fluid flywheel. Tuning the preselector for narrower bandwidth (or higher, or greater selectivity) increases this loss. Some early petrol- and diesel-engined railcars in the 1930s used the Wilson preselector gearbox. The epicyclic preselector gearbox allowed a clear flat floor for driver and front seat passenger.