Description Piezo discs are great for constructing pickups for acoustic instruments. Many users love them as the pickup in cigar box guitars, and they are a favorite amongst people experimenting with electric drum triggers.This item is well made of premium material for long lasting and practical use. Feature - Color: As shown. - Material: Copper. - Size: Approx. 2.7 x 2.7 cm / 1.1 x 1.1 inch (L x W). - Resonant Frequency: 4.0 plusmn;0.5 Khz. - Resonant Impedance: 200 Omega; Max. - Static Capacitance: 25.0nFC30%at 100Khz. - Input Voltage: 30Vp-p max. - Operating Temperature Range: -20-70. - Storage Temperature: -30-80. - Plate Diameter: D=27.0 plusmn;0.1mm. - Ceramic Disc Diameter: d=20.0 plusmn;0.3mm. - Metal Plate Thickness: t=0.20 plusmn;0.03mm. - Total Thickness: T=0.45 plusmn;0.05mm. - Lead Wire Specification: UL1571 AWG 28# 2.54mm Terminal. - Features voice legible, contactless, thin and light. - 27mm brass outer diameter plate. - Low voltage and low power consumption. - Great for acoustic instrument pickups, stomp boxes, mics, etc. - Suitable for clocks, toys, cameras, telephones and so on.Packing list: 10 x 27mm Piezo Disc Diaphragm Elements Thicken Buzzer Copper Sheet Piezoelectric Ceramic Chip with Leadwire