This is a bass overdrive pedal equipped with a 12AY7 vacuum tube. Discontinued product. The manufacturer is a Greek effects builder, renowned for its unique character in its product lineup. The LOCOMOTIVE was reportedly designed with the distortion of large tube amps like Ampeg in mind. It's one of the few bass distortion pedals equipped with a real vacuum tube, and its clear and powerful tone is a key feature. The gain control adjusts the amount of distortion. The gain range is wide, from warm, low-gain tube sounds to a quite powerful distortion when the gain is maxed out. Independently of the distortion amount, you can adjust the volume of the distorted channel (mean) and the volume of the clean signal (clean) individually, allowing you to mix the original sound at any balance you like. The tone control adjusts the high frequencies and only affects the distorted channel. It is powered by a 9V center-negative power supply. True bypass. The vacuum tube can be replaced with any tube you like. This product has not been modified. Operation has been confirmed to be normal.