12PCS 27mm Piezo Discs with Wire Brass Piezoelectric Disk Piezo Pickup Transducer for Acoustic Guitar Drum Trigger1DISC SPECIFICATION: The piezoelectric pickup disc has a diameter of 27mm and a thickness of 0.4mm, with about 48cm wire, which is lightweight, thin, and durable. 2GOOD PERFORMANCE: The resonant frequency is 4.60.5KHz, the maximum resonant impedance is 300, this piezo disk has low power consumption and high sensitivity. 3APPLICABLE RANGE: These pre wired piezoelectric discs have compact size, suitable for cigar boxes, guitars, pedals, as well as various string and percussion instruments. 4BRASS MATERIAL: These piezoelectric pickup discs are made of excellent brass material, with good stability, high temperature resistance, and has a long service life. 5MULTIPLE USAGES: Including 12 piezo discs, suitable for beginners to use in touch sensor, electronic drum trigger, buzzer, for making contact microphone, watch, electronic toy, etc.