1. Function: Digital power display, detachable design, weld-free assembly, reverse polarity protection. Supports charging of up to 21 x 18650 flat-top batteries. Built-in battery allows use as a portable power bank. Standard version requires a charging cable; wireless fast-charging version supports cable-free 15W wireless charging. 2. DIY portable power bank kit — customizable, high-capacity, and durable for reliable charging performance. 3. Designed for users with high power demands. Features three built-in charging ports: Micro-USB, Lightning (for Apple devices), and USB-C. Compatible with charging cases. 4. Real-time power level display enables convenient monitoring of remaining capacity for efficient charging of smartphones and other devices. 5. Includes a carrying lanyard for easy portability. Model: T21 Series with LED indicator Battery Support: 21 x 18650 flat-top batteries (weld-free installation) Dimensions: 170mm (L) × 84mm (W) × 62mm (H) Internal Dimensions (excluding springs): 129mm (L) × 74mm (W) × 55mm (H) Specifications (T21-PD-QI with LED): Output: 5V–3A, 9V–2A, 12V–1.5A, 4.5V–5A, 5V–4.5A Wireless Charging: Up to 15W Safety Precautions: 1. Do not use batteries with damaged outer casing. 2. Only flat-top 18650 batteries are compatible — button-top batteries are not supported. 3. Ensure correct orientation of positive and negative terminals during installation. 4. Avoid use or storage in high-temperature environments. Color: Black Material: ABS plastic Package Includes: 1 × 18650 Power Bank Case (batteries not included) Note: Actual product color may vary slightly due to screen settings and lighting conditions. Dimensional tolerance: ±1–3 cm.