[High quality] made of copper, high temperature resistant, stable, durable and long lifespan [Size] Piezo pickups, have a diameter of 27mm, simple and easy to use, these pre-wired Piezo pickups, can be easily installed in a cigar box guitars, foot pedals and other home instruments to detect sound and vibration [Widely used] very suitable for beginners as press equipment, triggers electronic drums, buzzers, making your own press microphone, also used in watches, cameras, mobile phones, electronic toys, computers, etc. Size: 27mm copper sheet diameter Material: Copper Color: Gold Package Content: 15 x Acoustic Pickup Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement error is +/- 1-3cm.