| 1930 FARMER Sound Amplifying Horn Patent Print |
| 1930 FARMER CLYDE Pneumatic Horn Patent Print |
| 1930 HARRISON HENRY Acoustic Horn Patent Print |
| 1930 REESE Closed End Resonating Horn Patent |
| 1930 DORSEY Electromagnetic Horn Patent Print |
| 1930 RCA CORP Loud Speaker Horn Patent Print Art |
| 1930 E A LAB INC Pneumatic Horn Patent Print Art |
| 1930 SPARKS WITHINGTON CO Horn Projector Patent |
| 1930 MCCUNE Vacuum Operated Horn Patent Print |
| 1930 DYCK ARTHUR Loud Speaker Horn Patent Print |
| 1930 ORA DOTSON Horn CONN LTD C G Patent Print |
| 1930 JONES Sheet Metal Horn Elbow Patent Print |
| 1930 ASHLEY MERWIN Horn Patent Print Art |
| 1930 BILLIG FRED Horn Projector Patent Print Art |
| 1930 GULICK EDWARD Horn CONN LTD C G Patent |
| 1930 MUELLER Sound Amplifying Horn Patent Print |
| 1930 ABRAHAMS Loud Speaker Horn Patent Print Art |
| 1930 MALLORY Horn Art Print Patent |
| 1930 HORN ARMSTRONG Steering Gear Patent Print |
| 1930 HARRY Sound Reproducting Horn Patent Print |
| 1930 CONN LTD C G Horn Patent Print Art |
| 1930 WILDER SAMUEL Horn Patent Print Art |
| 1930 WESTINGHOUSE ELECTRIC & MFG CO Horn Patent |
| 1930 BUELL ROY Horn Patent Print Art |
| 1930 AUFIERO JOHN Pneumatic Horn Patent Print |
| 1930 BUTLER AMES Heterodyning Horn Patent Print |