Features: 1. 1A Linear Charging – Provides stable, efficient charging with adjustable current up to 1A, suitable for 18650 lithium batteries. 2. High Charging Accuracy – Voltage precision within 1.5%, with a full charge cutoff at 4.2V to protect battery health. 3. Wide Input Voltage Range – Works with 4.5V–5.5V input via Micro-USB port, compatible with common adapters and power banks. 4. Clear Charging Indicator – Red LED light stays on during charging; turns off when battery is fully charged. 5. Compact & Durable Design – Made with metal components and sturdy PCB, operates reliably in temperatures from -10°C to +85°C. Product Details: This lithium battery charging board offers safe, linear charging for 18650 cells. It supports 1A adjustable charging current, accurate voltage control, and reverse connection protection. The Micro-USB input makes it easy to use with standard chargers. Ideal for DIY battery packs, portable devices, and repair projects. Specifications: - Charging Mode: Linear - Charge Current: 1A (adjustable) - Charging Accuracy: ±1.5% - Input Voltage: 4.5V–5.5V - Full Charge Voltage: 4.2V - Indicator: Red LED (on while charging) - Input Interface: Micro-USB - Operating Temperature: -10°C to +85°C - Reverse Polarity Protection: Yes - Weight: 18g - Material: Metal (main components) - Color: Blue - Package Includes: 10x lithium battery charging boards Note: Slight color variations may occur due to lighting or screen settings. Dimensions may have a tolerance of +/- 1–3cm.