PREMIUM MATERIAL: Made of high quality material, durable and lightweight to carry and storage. MULTI-FUNCTION: It can contact microphones pick up sound by having direct contact with the sound source, which can effectively eliminate external sounds interference and not be influenced by sound reflections from nearby objects, offering a better tone sound. EAST TO INSTALL: Easy to install and removable self-adhesive design allows you stick it anywhere on your instrument, and never cause harm to the surface of instrument. WIDE APPLICATION: Fit for almost string music instruments such as acoustic guitar ,violin ,mandolin ,banjor etc. Perfect accessory for DIY CD of players. The Guitar Piezo Pickup Transducer is durable and lightweight to carry and storage. It can contact microphones pick up sound by having direct contact with the sound source, which can effectively eliminate external sounds interference and not be influenced by sound reflections from nearby objects, offering a better tone sound. Specifications: Material: Metal Color: Black Length: 30CM Sensor Diameter: Approx. 2.7 cm / 1.06 inch Jack: 1/4 inch (6.35 mm) Weight: Approx. 30 g Package Included: 3 x Guitar Transducer 3 x Nut 3 x Gasket Installation instruction: 1 Take the plastic film down from the back of transducer to expose the adhesive. 2 Place the transducer through the sound hole to the lower part of the front body where the guitar produces the best tonal response. 3 Drill a hole from inside the body, loosen the end-pin jack nut, insert it to the hole and tighten the nut. Above the procedures for referring depends on different instrument Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.