All of our barometers are fully adjustable. Adjustment can be made by turning the small brass screw on the back of the movement until the barometer needle is set on the current pressure for that geographic area on that day. (The screw is seated in a small indentation. Do not unscrew the 2 larger screws as the movement will disassemble.) After setting, move the gold needle on the glass over the registering needle so you can easily observe any rise or fall.

Any change in altitude will necessitate having to reset your barometer. The standard barometer movement is for altitudes from 0 to 3500 feet above sea level. Movements for high altitudes (up to 7000 ft.) are available for certain models.

• All models are accurate to +/- 3 millibars.
   
• All barometer movements are aneroid with 1 sealed baffle.

To assure that your barometer is working properly, you can do the following tests:

• Using the small brass adjusting screw, turn it so that it makes and arc from the 8 o'clock position to the 4 o'clock position and back again. It should do this smoothly and without sticking. Be careful to not unscrew so far that the screw falls out.
   
• Place the barometer in a clear plastic bag, blow air into it and seal tightly so the air will not escape. Gently push down on the bag. If your registering needle moves several millibars, it is most likely working as expected.