Input Voltage: 5V DC (USB PLUG) Loudspeaker Output Power :3W * 2 RMSPower supply : USB portFrequency : 90Hz- 20kHzInput Resistance : 4 OhmWorks well with: Laptops / Notebooks/ Netbooks and when using external power source (e.g. power bank) they can be used with MP3 players / Mobile Phones / Smartphones, tablets, etcSize of 1 speaker: 62 x 62 x 54mm...