Hyper Power lithium battery energy storage unit, likely intended for solar or inverter backup systems.
From the visible label near the bottom, it appears to be:
* 25.6V
* 165Ah
* LiFePO4 (Lithium Iron Phosphate) rechargeable battery
* Energy capacity is likely around 4.2 kWh (25.6V × 165Ah ≈ 4,224Wh)