Very easy to install and performed well with several different amplifiers. Plug Diameter: 6.35mm / 0.25 inch; Cable Length: 35cm / 13.78 inch. Suitable for guitar, violin, ukulele, mandolin, and banjo. Effectively reduces interference from external sounds and is not affected by sound reflections from nearby objects. Material: Metal. Color: Black. The sound pickup features a high-quality 27mm piezoelectric ceramic disc transducer. Its large size allows it to capture a broad range of sound, helping to ensure optimal sound collection even if the ideal placement location is uncertain. This is a pre-wired, pre-soldered piezo and jack harness, making installation simple. Just attach the piezo inside or on your instrument, drill a hole, and mount the jack—then it's ready to use. Compatible with most string instruments such as guitar, mandolin, violin, ukulele, and banjo. Installation instructions: 1. Remove the plastic film from the back of the transducer to expose the adhesive. 2. Place the transducer through the sound hole to the lower part of the front body where the instrument produces the best response. 3. Drill a hole from inside the body, loosen the jack nut, insert the jack, and tighten the nut securely. Note that exact steps may vary depending on the instrument. Cable length: 32cm. Plug diameter: 6.35mm / 0.25 inch. Package included: 1x pickup, 4x gasket, 1x knob. Note: Light reflection and differences in display screens may cause slight variations between the color shown in the image and the actual product. Measurement tolerance is +/- 1-3cm.