| CFHU • Carbon Filter Housing |
| DFFU • Double Flat • Filter Housing |
| FFHU • Flat • Filter Housing |
| FPHU • Fan Pack Housing Unit |
| HFHB • HEPA Filter Housing • Swing Bolt |
| HFHC • HEPA Filter Housing • Crank Style |
| SFHU • Standard • Two-Stage Filter |
| VBFU • Vee Bank Filter Unit |