4 AA Rechargeable Batteries, 2500mAh each.
Compatible with PowerShot SX1, SX10, SX110, SX100, S5, S3, S2, S1, A2100, A2000, A1100, A1000, A720, A710, A700, A650, A640, A630, A620, A610, A590, A560, A550, A540, A520, A510, A530, A480, A470, A460, A430, A410, A400, A310, A300, A200, A100, A95, A80, A40, A20, A10, E1 and any other digital camera that is powered by AA batteries.