Features: Brand new and high quality. Dimensions Piezo pickup plate diameter 35mm, thickness 0.4mm. Wire length 250mm (10 inches) Small, thin, high performance Resonant frequency 1.8 +/- 0.3khz, resonant impedance max 300 ohms, low power consumption, high sensitivity. Easy to use These pre-wired piezo pickups are easy to install and use in box guitars, pedals and other homemade musical instruments for sound and vibration detection. Widely used, great for beginners to use as touch sensors, electronic drum triggers, buzzers, make your own contact microphones, also used in watches, cameras, mobile phones, electronic toys, computers, etc. Specifications: Base material: Brass. Dimensions: Center disc diameter 35mm, thickness 0.4mm, wire length 250mm. Type: External drive type element.