Sony NP-BX1 (NPBX1.CE)
X-Series Rechargeable Battery Pack.
Key features:
Lithium ion Type X rechargeable battery
Approx. capacity: 3.6V / 4.5Wh (1240mAh)
Approx. dimensions: 29.9 x 9.2 x 42.7 mm (WxHxD)
Approx weight: 25 g