A hygrograph uses a length of hair to record changes in air humidity.
Operating range: 0 to 100% RH at an accuracy of +/- 3% between 20 and 100% RH
It is fitted with either a quartz clock or a clockwork motor.

Mechanical drum clock acc. to Din 58658
revolution cycle – day 25.6h (Model 325)
week 176h

Electronic Quartz clock
revolution cycle – day 25.6h (Model 325Q)
week 176h
month 783h

Please specify the clock type when ordering.