For monitoring the quality of spun yarn or detecting broken filaments. The portable battery powered unit uses an infra red detecting head while low power circuitry ensures a long battery life,typically 10 hours. A two line intelligent display(LCD) shows the measurement time (seconds) and count. If the batteries are low on charge a message will appear requesting the batteries to be charged. Measurement time is selectable in increments of 5 or 10 seconds. minimum is 5 seconds and the maximum is 95 seconds. For broken filament detection there is a continuous mode where the Hair Scan will monitor until the operator decides to finish. Measuring head can be fixed permanently in the threadline.