Detail LUTRON AM-4200 Anemometer : 

Features : 

• High quality with the economical cost
• Pocket and compact housing case
• Separate probe, convenient for the remote measurement
• Low-friction ball vane wheels in accurate in both high and low velocities
• Multi-functions for air flow measurement : m/s, km/h, ft/min, knots. mile/h.
• Fast and accurate readings with LCD display
• Battery power source from 006P DC 9V batteries
• Used the durable, long lasting components including a strong, light weight ABS-plastic housing case
• Wide applications : use this anemometer to check air conditioning and heating systems, measure air velocities, wind speeds, temperature etc

General Description :

• Display : 13 mm (0.5 inch) LCD. 3 1/2 digits
• Measurement : m/s, km/h, ft/min, knots. mile/h.
• Sensor structure : Conventional twisted van arm and low  friction ball bearing design
• Sampling rate : Approx 0.4 second
• Operating Temp. : 0^◦C  to 50 ^◦C  (32^◦F to 122^◦F)
• Operating humidity : Less than 80% RH
• Power Supply : 006P DC 9V battery (heavy duty type )
• Power current : Approx. DC 6 mA
• Weight : 381g/0.84 LB
• Dimension : 
  Main instrument : 180x73x23 (4.3×2.9×1.4inch)
  Sensor head : Round 72 mm dia
• Weight : 260g/0.58 LB (including battery)

Description： ANEMOMETER
Model : AM-4200
* 0.8 to 30.0 m/s, ft/min., km/h, knots.
* Pocket size, economical cost.
* Low-friction ball-bearing vane.
* 131 x 70 x 25 mm, Sensor – 72 mm dia.
* Separate probe, high reliability.