Compact 28mm Iron-Cased Speaker 28mm diameter; 8 ohm impedance; 1w power rating; 0-20khz frequency range; iron cased for durability; Plug-and-Play Compatibility Compatible for arduino and raspberry pi; no complex driving circuits required; easy integration into diy projects; Stable Performance with High Pass Rate Designed for long service life; stable operation in various electronic devices; reliable for alarms and alerts; Wide Application Support Suitable for digital displays, security systems, printers, and smart home devices; versatile audio solution; Clear Sound Output with Reliable Build Delivers loud and clear sound; iron casing protects internal components; suitable for compact and portable electronics