Tree box filter

A Tree Box Filter (TBF) is like an imaginary box with a tree inside it. The tree is made up of little branches that can catch bits of wind and block some things from getting in or out. The tree box filter works like a sieve -- the little branches stop certain things (like dust or smoke) from getting into the box and mixing in with the air. When you need clean air, the tree box filter will help keep it clean by trapping the dirty stuff before it gets into the box.