Manual sample-draw kit WARNING The sensor ports must be kept free of obstruction. Blocked sensor ports can lead to inaccurate and potentially dangerous readings. In diffusion mode, the atmosphere being measured reaches the sensors by diffusing through vents in the bottom of the instrument. Normal air movements are enough to carry the sample to the sensors. The sensors react quickly to changes in the concentrations of the gases being measured. Diffusion-style operation monitors only the atmosphere that immediately surrounds the detector. The IQ Force can also be used to sample remote locations with either the hand-aspirated sample-draw kit, or with a motorized sample-draw pump. During remote sampling, the gas sample is drawn into the sensor compartment through the probe assembly and a length of tubing.