Holy Grail Nano contains three different reverb algorithms: Spring, Hall and Flerb. All three algorithms were designed and tailored for the electric guitar but they will work equally as well on most instruments and voices. The Spring algorithm is a recreation of the classic spring reverbs that are found in many guitar amplifiers. The Hall algorithm is a new, lush reverb. Flerb is a beautiful reverb like nothing you have heard before. Holy Grail Nano will change the way you look at reverb! electro-harmonix Holy Grail Nano Reverb Features:Three different reverb algorithms: Spring, Hall, and FlerbGreat for guitar, voice, and most any instrument. Digital reverb in a compact pedalelectro-harmonix Holy Grail Nano - Amazing reverbs in a compact pedal!