Bought this new for a amp I sold and did not want to include this audiophile fuse. Purchased from authorized deal, totally authentic part.
F= Fast Blow 2 AMPS 5x20 size.
Synergistic Research Quantum Fuses employ a custom alloy treated with 2,000,000 volts of electricity! SR Quantum Fuses significantly outperform all other high-end fuses on the market and are guaranteed to deliver a noticeable increase in sound staging, resolution and air thanks to a lower noise floor and blacker backgrounds.