The sound pickup is high-quality 50mm Piezoelectric ceramic disc ducer It is very and can collect a wider range of sound in case you are not 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 ducer to expose the adhesive 2 Place the ducer 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 -pin jack nut, insert it to the hole and tighten the nut The above procedures depend on different instruments. Specification: color:black Material: metal + plastic Cable long : approx 42cm/165 inch Plug Dia: approx 635mm/025 inch Package included: 2 x Disc piezo pickup Only 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.