Material: Battery charger module made of electronic components.Can be used for multimeter, converted to lithium battery charging. Features: Battery charger module combines the TP4056 battery charger with a boost circuit. Adds a battery and converts a low power DC device to a USB rechargeable device. Instructions for use: TP4056 Charger Module can be used for multimeter to convert to charge lithium batteries. VIN+ port input 5V solar panel, BAT+ port can output 4.2V to charger 3.7V 18650 battery. Small and delicate: 1.3in*0.92in/33mm*23mm Package contains: 6 * Lithium Li-ion Battery Charger Module