When evaluating book reading lights, prioritize LED efficiency and color temperature control. Look for products offering 3 to 5 adjustable modes (e.g., Warm, Natural, and Cool White) ranging from 1600K to 6000K. Ensure the CRI (Color Rendering Index) is above 80 to reduce eye strain. For rechargeable models, a lithium-polymer battery capacity of at least 500mAh to 1000mAh is standard, providing 20-70 hours of illumination depending on brightness settings. Additionally, verify the clamping force and neck flexibility, ensuring the gooseneck can withstand at least 5,000 bends without losing structural integrity.