Product Name: Replacement Internal Battery for Vivo S1 Pro (Y7S)

Model Number: B-K3

Compatibility: Fits Vivo S1 Pro / Y7S device

Condition: Brand New / High-quality replacement

Battery Type: Lithium-Ion Rechargeable Battery

Capacity: 4350mAh - 4500mAh (typical for S1 series)

Voltage: 3.85V

Safety Features: Built-in protection circuit against overcharging, over-discharging, and short circuits

Function: Direct replacement for old, worn-out, swollen, or failing original battery