The BioFilter is an inline bacterial viral filter designed to minimize the spread of germs with a minimum loss of air flow; allowing students to still hear each other. Each unit is sonically sealed so there are no chemical adhesives or unwanted material residue. This Inline filter is easy to install and does not require any tools for assembly. BioFilter snaps together with the tubing and the Orange or Blue phones found in WhisperPhone DUET and SELECT systems.