Identifying a directional reference using rate gyros...

Illuminated level

Illuminated level

Illuminated level

Illuminated spirit level

Illuminated spirit level

Illuminated spirit level

Illuminated spirit level using fiber optic devices

Illuminated spirit vial and level

Illuminating device for a magnetic compass

Illuminating navigation device

Inclination and acceleration sensor utilizing electrostatic capa

Inclination and direction responsive apparatus

Inclination angle detector

Inclination angle reader and method for using same

Inclination detector device with a closed optical path

Inclination indicating apparatus

Inclination instrument

Inclination measurement apparatus

Inclination measurement apparatus