The 4000 is a compact backup battery that extends the life of your average smartphone by up to 2 full charges. Perfect for the commute or day trip. All Swiss Mobility chargers come pre-charged and ready to use out of the box; compatible with Android and iOS Mobile Phones and Tablets, cameras and more. 4000 mah Universal Power Pack with built-in safety light. High Speed Safe Charging. Integrated charge indicator telling you how much charge remains in your charger. Up to 18 hours Additional Talk Time. Pre-Charged & Ready for Smartphones and Tablets. Ultra Compact Design with Safety Light. Premium soft touch casing.