Fischer Instruments 111-01 Stainless Steel 4" Human Hair Hygrometer

I bought 3 of these to monitor humidity on different floors of my business. Placed them all next to each other on the wall just to check them out, and 1 day later, the readings show '52%", "64%" and '39%'. That comes to a 25% difference. So I follow the instructions for calibration with the long soak in a warm damp towel. Calibrate each one to 98%. Put them back together on the wall and let them sit overnight. The next morning, we are reading '55%", '47%' and '38%'. Repeat the calibration again, and still a huge variance more than 12% between them. With my calibrated Fluke humidity probe. the correct reading in that area should have been 41%.So this implies to me that these are NOT precision instruments, but closer to the cheap thermometers you can buy at the hardware store (take a look at the variance they read next to each other in the store). Plus the calibration adjustment is hyper-sensitive, and almost impossible to use. Hardly touch the adjustment screw, and the reading changes about 20%.These are worthless as precision humidity gauges, so save some money and try something else.PS. The scale is linear on one of the three I bought, and logarithmic on the other two. Not sure why.

accurate abd responsive

Seems to work accurately , but I have nothing more accurate to calibrate it with .

Looks great and works perfect! Well made and super accurate! My cigars are loving the accuracy!