3 Transducer Pickup System fit for most string music instruments, amplify an upright bass, banjo, violin, ukulele, viola, cello, mandolin, and a resonator guitar
The plastic squares is a self adhesive block to mount the extra wire in your box, without pre amp they will work well.
No Battery and Soldering Required, pre-wired piezo mic save time for you, easy to install, convenient to use
Cable Length: approx. 57cm/ 22.44", 3-pack Piezoelectric Disk Dia.: approx. 27mm/ 1.06", Endpin Jack Dia.: approx. 6mm / 0.24"
Material: Plastic, Electronic Part: Metal, Color: black lines, silver tone (Any other problem about product or replacement, please help to contact us, The way to Contact Seller: Find your order -- Contact Seller, then email to us, thanks.)