The efficient operation of your school's fume hood is essential to your well-being and that of your students. A device we use to check fume hood efficiency is known as a velometer. The device measures air velocity. A complete reading is expressed as linear feet of air per minute. To check hood efficiency, measure the air velocity at the “face” of the hood opening. Ideally, you would make such measurements at multiple locations across the face of the hood. A hood should provide air movement of at least 100 linear feet of air per minute. The device is easy to use. The unit must be level during use; therefore, a bubble level is built in. The unit is calibrated from 0 to 400 feet per minute. Accuracy is ±10%, full scale. The carrying case is available to protect your instrument during storage or to enable you to transport the unit safely from hood to hood or school to school.