KEEDOX&reg; 5.25" PC Media Dashboard Front Panel All-in-1 Card Reader USB Gravo SATA/ESATA/IDE 3.7V rechargeable replacement battery 300mAh , fit for MP3, MP4, BlueParrott B250-XT Wireless Bluetooth Headset Nominal voltage 3.7V, fully charged, 4.2V, 250mAh capacity of battery, Power 0.925Wh ,item model PL603450, Built-in battery protection circuit module to prevent overdischarge and short circuit of this battery. Battery size: 30 x 25 x 5 mm / 1.18 x 0.9 x 0.2 inch (L*W*T) Connector Type: 2-Pin Pitch 1.25mm; Cable Length: 2 inch, Before replacing, please contrast with the old battery and check the polarity of the battery. Red wire connection power positive " +" , Black wire connect power negative pole "-". if is a reversed, you need position of interchange wires.