Applicable: You can use this charger with an AstroAI battery pack, AstroAI handheld battery-powered air compressor, and AstroAI multifunctional air pump. These products can achieve the best performance while using the charger. Not available for C1. ETL Certified: High-quality, safe, and reliable; provides a safer experience for you. High Power + Fast Charging: 1.7A power + 21V voltage; one hour to fully charge the battery pack. LED Indicators: Indicators that display the charging status. Enjoy Our Product: Please feel free to contact us if you have any questions. AstroAI always provides customers with the best service. AstroAI charger