Vilros Mini Bluetooth Speaker The Vilros Small Bluetooth speaker packs a large 90DB sound despite its small 30mm Diameter SizeIts small size and powerful sound makes it ideal for use with a Raspberry Pi Board.The Speaker includes a small cable so that it can be charged via a Raspberry Pi Board while it is in use. Specs Product Size: 35.6 x25.lmm Range: up to 10 Meters Working time on full battery charge: 1-3 Hours Battery Capacity: 3.7V/140mAh Power Rating: PO IW Transmitting Freq:- 150Hz-16KHz Bluetooth Version: 4.2 Output Power: 1W New Weight: 21G Speaker Parameter 30mm Diameter Signal-to-noise ratio: 90DB