50mAh LiPo Battery 1S 3.7V, Max Discharge Rate 10C, 0.5A, With a plug with 1.25mm 2P JST.  Only suitable for coreless motors with a diameter of 6mm (6mm, 4mm)!!

Size:19X12X5mm

Very small

Front

Back

With GH1.25mmJST 2P Plug

The weight is about 1.55g