Item Type: 7. 4V RC Lithium Battery_x000D_Weight: 37g/1. 3oz_x000D_Material: Lithium polymer_x000D_Battery Capacity: 520mah lithium battery (shipped with pure battery)_x000D_Voltage: 7. 4V 1Compatibility with Various Models: This RC 1/28 battery is compatible for WLtoys P939, K979, K989, MINI Q, and MINI D models. It provides a seamless fit and reliable performance, making it a versatile choice for RC enthusiasts. 2Portable Design: The lithium battery's compact design makes it easy to carry around. It offers the perfect balance of weight, power, and performance, ensuring a smooth and enjoyable experience. 3Durable Lithium Polymer Construction: The lithium battery's outer casing is made from lithium polymer materials, ensuring durability and stability. It is built to withstand rigorous use and has a long lifespan, providing reliable power for your RC boats. 4Extended Battery Life: The longevity of the durable lithium battery allows for extended playtime, maximizing the enjoyment of your toys. With this battery, you can fully immerse yourself in the excitement without worrying about frequent battery replacements. 5Built in Overcharge and Short Circuit Protection: Safety is a priority when it comes to charging your RC boats. The lithium battery is equipped with overcharge and short circuit protection, ensuring a safe and secure charging process.