U.S. federal trademark · Serial No. 74305575 · Reg. No. 1765704
dual telephone system comprising two telephones, one located on each side of a transparent barrier to allow easier communication through the barrier, sold with or without amplification means provided within the telephones to improve the quality of sound by eliminating unwanted background noise
Source: USPTO federal trademark records. Informational only, not legal advice. Status and details may lag the live USPTO database.