The sound pickup is high-quality 50mm Piezoelectric ceramic disc transducerIt is very large and can collect a wider range of sound in case you are not sure where are the best parts of the sounds.This is a pre-wired, pre-soldered piezo and jack harness which make it easy for you. All you have to do is to attach the piezo in or on your build, drill a hole and mount the jack. Then you're done Fit for most string music instruments such as Guitar Mandolin Cigar box Guitar Violin Ukulele Banjo, etc.Installation instruction:1 Take the plastic film down from the back of transducer to expose the adhesive2 Place the transducer through the sound hole to the lower part of the front body where the guitar produces the best tonal response3 Drill a hole from inside the body, loosen the end-pin jack nut, insert it to the hole and tighten the nutThe above procedures depend on different instruments.Specification:color:blackMaterial: metal + plasticCable long : approx 42cm/16.5 inchPlug Dia: approx 6.35mm/0.25 inchPackage Contents:6 x Disc piezo pickupOnly the above package content, other products are not included.Note: Light 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.