Type: Bluetooth speakerConnection method: 3.5MM audio jackInterface type: card readerOutput power: 5W*4Signal to noise ratio: ≥75dBPower supply mode: built-in lithium batteryChannel: 2Playing time: 8 hoursExpansion storage: 32GBBluetooth protocol: 4.0Number of speakers: 2Effective distance: 15 metersFunction: insert card, radio, voice prompt, call functionOperation mode: buttonApplicable people: generalDisplay: NonePlay format: MP3, WMAShell material: metalSpeaker adjustment method ButtonIs there a radio function: NoneBox material: metalAppearance size: 550*50*50mm