Features: High decibel SFM-20B DC3-24V continuous sound buzzer, 2312 active piezoelectric buzzer. Stable structure, quality ABS material, environmentally friendly, flame-retardant. Integrated electronic loudspeaker consists of multiple harmonic oscillator, a piezoelectric buzzer chip, impedance matching unit, a resonator, and a housing. Easy to operate, connection to the rate power supply, buzzer continuously beeps, easy and convenient to use. Widely used as sound devices in electronic product circuits such as computers, printers, copiers, alarms, electronic toys, automotive electronic devices, telephones, timers, etc. Specifications: Material: ABS Diameter: approx. 23mm/0.9inch Model Number: SFM-20B Rate voltages: 12V Voltages: 3-24V Rate current: up to 12mA Sound pressure level: 87dB Working frequency: 3300±500Hz Quantity: 10pcs/set Package Includes: 10Pcs Buzzer note: Please allow 1-2cm errors due to manual measurement. Please allow for slight color differences due to different display resolution.