This battery is originally for the Solo 4 model, which was released in 2024 with the model (A3140) that can be found on the inside of the right panel and on the right hinge for the older models. You can also use this same exact battery as an UPGRADE to your Solo 2 (B0534) and Solo 3 (A1796) headphones models. All of the other models typically have a 350mAh battery so this upgrade would give your headphones a longer-lasting battery. This means you dont have to charge your headphones as often. Choose JoesGEcom for quality electronics at affordable prices. Our established dealership, founded in 2014, offers years of experience and expert guidance on how to save money on top-brand electronics. We provide parts, sales, repair services, tools, and guides for all the products we sell. Our unique approach sets us apart from other online sellers - we don't just sell parts, we use them in our own repair center to ensure they are fully functional and compatible. Located in Maple Falls, WA, we pride ourselves on our exceptional pre and post-sale customer service. With nearly 1,000 repair videos, our archive has answers to almost all your questions. Trust JoesGEcom to deliver accuracy, variety, and support.