Here is the professional, SEO-optimized English product description for your Infinix Note 12i (BL-49KX) replacement battery:

Infinix Note 12i Replacement Battery (BL-49KX) – 100% Premium Quality

Is your Infinix Note 12i losing power rapidly, running warm under load, or failing to hold a charge throughout your busy workdays? Restore its factory-fresh endurance with our premium-grade BL-49KX replacement battery. Manufactured to match exact original performance standards, this high-capacity battery provides the steady and efficient power supply needed to back your daily app usage, photography sessions, and crisp media streaming just like day one.

Key Features:

• Flawless Physical Fit: Tailored specifically for the Infinix Note 12i (Battery Model: BL-49KX / Model: X663, X663B), ensuring an exact structural match and secure connector alignment with the phone's internal logic board.

• True 5000mAh Power Capacity: Packs a full standard 5000mAh capacity to completely revive your smartphone's multi-day standby endurance and daily screen-on hours.

• Advanced Smart IC Protection: Features a built-in intelligent safety microchip that actively protects against over-charging, over-discharging, unexpected overheating, and short-circuits to secure your phone's hardware.

• High-Density Lithium Polymer Cells: Built using advanced Lithium-ion polymer technology for ultra-stable voltage output, entirely eliminating erratic percentage jumps and sudden unexpected power cuts.