Decagon Devices pawkit Operator's Manual page 22

Pawkit User Manual
4. Operation
2. Place your prepared sample cup onto a level surface:
Next, place the opened Pawkit onto the prepared sample
cup. The cup will fit under the sensors into a recess in
the bottom of the Pawkit. 
A correctly positioned cup will result in the Pawkit
being level on the bench when sitting on the cup and the
sensor cover legs. Ensure the cup is entirely within the
recess. Otherwise, the Pawkit will not be level on the
bench and the cup will not make a vapor seal with the
sensor.
Final sample cup placement
18