FSM III
| Brand | Kustom Acoustics |
| Manufacturer | Kustom Acoustics Inc. |
| Function | Speaker |
| Produced | 1976 |
| Country | United States |
| Model ID | Floor Standing Monitor III |
| Form Factor | Floorstanding |
| Signal Path | Passive Hardware |
| Dimensions | 43.2 × 76.2 × 33 cm (W × H × D) |
| Weight | 88lbs |
| Treble | 1.75" Semi-Dome |
| Midrange | 5" Cone |
| Bass | 12" Paper Cone |
| Impedance (Nominal) | 8Ω |
| Crossover Frequencies | 775Hz, 3.5kHz |
| Recommended Amplifier Power | 15-250W |
| Power Handling | 250W |
| Enclosure Type | Transmission Line (TAL (Tapered Acoustical Line), Var-I-Vent) |
| Finish | Walnut, Fired Pewter Top |
| MSRP (1976) | $379 |