E series: we adopt more succinct design methods in the design of E series of products, and additional rotary knob isn’t installed onto the potentiometer, which leave the plastic part of the potentiometer directly exposed at the product surface. This shows the style of being smaller and more succinct, and embodies a refined industrial product design. The bottom of the product adopts wholly sealed metal shell to efficiently reduce noise, and this series of products that adopts piezo ceramics pickups is featured with large output, compact bass and invigorative alto voice and clear and loud high pitch, which exhibits the timbre featured by the excellent piezo ceramics pickup.