The CR Box comprises four air filters commonly used in heating, ventilation, and air conditioning (HVAC); a cardboard base; and a box fan to draw air through the filters and toward the ceiling.

Homemade air purifiers can filter air faster, making them an affordable alternative to more expensive commercial products.

The CR Box is made up of four air filters commonly used in heating, ventilation, and air conditioning (HVAC); a cardboard base; and a box fan to draw air through the filters and toward the ceiling.