Catalinbread Karma Suture Germanium Harmonic Fuzz Guitar Effects Pedal Extremely versatile fuzz pedalto be used in several applications Built on a rare and obscure circuit known as the Harmonic Percolator. This circuit has the amazing property of generating predominantly even-order harmonics - which creates an amazingly sweet and clear distortion. Ability to play complex jazz chords through it and every note rings sweet and clear. So, using the original circuit as the springboard, they created the Karma Suture.