High-Efficiency Particulate Air is a standard of air filter. By this standard an air filter must remove 99.97% of all particles greater than 0.3 micrometre from the air that passes through.
A device with an allergy filter can remove allergens and dirt from the physical surfaces in your home. It can make your indoor air cleaner and more breathable.
We consider a lower weight better because lighter devices are more comfortable to carry. A lower weight is also an advantage for home appliances, as it makes transportation easier, and for many other types of products.
The height represents the vertical dimension of the product. We consider a smaller height better because it assures easy maneuverability.
The width represents the horizontal dimension of the product. We consider a smaller width better because it assures easy maneuverability.