AC 4-wire method compatibility for accurate internal resistance measurements. Adjustable backlight brightness with 1-9 grade settings for improved readability in various lighting conditions. Data recording capability to store and compare 5 sets of resistance data for efficient troubleshooting. Intelligent power saving features with flexible standby time settings to optimize battery life. Fine-tuning functions for precise voltage and internal resistance measurements. Reliably test with the AC 4-wire method, ensuring accurate internal resistance measurements. Enhance readability with 1-9 grade backlight brightness adjustment for various lighting conditions. Easily store and compare 5 sets of resistance data for efficient on-site troubleshooting. Optimize battery life with flexible standby time settings, adapting to usage frequency. Experience precise measurements with voltage and internal resistance fine-tuning functions. Color: As Shown Material: plastic Package Contents: 1 internal resistance tester 1 4-pin cable 1 TS457 charging adapter board Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.