DC1700 Battery Operated Air Quality Monitor w/Accessories True Laser Particle Counter measures the concentration of particles in the air in 2 size ranges &gt;0.5 micron and &gt;2.5 micron diameter Accurately measure your home or neighborhood air quality and compare to AQI or PM2.5 Test your air purifier, HEPA air filter, or home/office air filtration efficiency 6 hour rechargeable Internal Battery or use continuously on AC power, 7 days of data storage with PC Interface CE marked and includes International Wall Adapter with plugs for worldwide use. Also ships with USB adapter cable.