Fender 4-Spring 600-Ohm Replacement Reverb Unit 600 ohm replacement 4-spring (4EB3C1B) reverb unit with RCA style input and output jacks Measures 16-3/4" Long decay design (2.75-4.0 seconds) Mounts horizontally to floor of cabinet with open side down Fits Hot Rod Deluxe/DeVille and Blues Deluxe/DeVille amplifiers manufactured from 1998-Present