Incl. protective cap, batteries and calibration protocol. The sensor of the testo 540 is adapted to the spectral sensitivity of the eye. This makes testo ideal for the measurement of light intensity. The Hold function allows an easy readout of the measurement values. Max. and min. values are displayed at the press of a button. testo 540 is very handy, small and easy to operate. - Hold function and max. / min. values. - Incl. calibration protocol. - Protective cap for safe storage. - Including wrist strap and belt holder. - Sensor adapted to spectral sensitivity of the eye. - Display light. Incl. protective cap, batteries and calibration protocol. The sensor of the testo 540 is adapted to the spectral sensitivity of the eye. This makes testo ideal for the measurement of light intensity. The Hold function allows an easy readout of the measurement values. Max. and min. values are displayed at the press of a button. testo 540 is very handy, small and easy to operate. - Hold function and max. / min. values. - Incl. calibration protocol. - Protective cap for safe storage. - Including wrist strap and belt holder. - Sensor adapted to spectral sensitivity of the eye. - Display light.