Feature:1. Applicable Model: 3.7V 520mAh lithium battery is suitable for Wltoys V977, XK K110, XK K110S remote control helicopter.2. 520mAh Capacity Battery: RC helicopter battery capacity is 520mAh, upgraded large capacity battery, provide longer service life.3. Strong Battery Power: Violent battery, strong power, stable and reliable performance, providing you great using experience.4. Replacement Parts: Easy to install and disassemble, you can directly replace the old or damaged parts to obtain higher strength.5. Light and Portable: Light in weight, small in size, easy to carry, will not increase your burden, can bring you more convenience.Specification:Item Type: RC Helicopter BatteryMaterial: Lithium ion, PlasticColor: BlueWeight: Approx. 123g or 4.3ozBattery Size: Approx. 58.5x16.7x6.5mm or 2.3x0.7x0.3inVoltage: 3.7VCapacity: 520mAhApplication: Suitable for Wltoys V977, XK K110, XK K110S Remote Control Helicopter.Package List:6 x Battery1 x Charger1 x Charging Cable