Fan speed indicator

Fatigue indicator

Faulty steam trap signal

Fence identification device

Fence wire location marker

Fender mounted visual signal device for a bicycle

Fever indicator

Fiberoptic flow indicator system

Field strength meter

File marking device

File marking device

Fill gate for grain bins and the like

Fill indicator for a vacuum cleaner dust collector

Fill level indicator for agricultural material bin

Filler and pressure indicator valve

Film cassette

Film registration device

Filter condition indicator

Filter differential pressure impending and bypass indicator

Filter restriction indicator