This is a listing for the L (left) earbud only, with a genuine new battery that has been replaced! The version is the latest version, 2.1.0 (^-^) Thank you for viewing! I run a battery replacement business in Hiroshima! My name is Chika, a repair and electrical work specialist (*^^*) This has been replaced with a new genuine battery (*^^*) It seems there are some unscrupulous businesses out there, and a friend consulted me because their battery failed for the third time. When I disassembled it, I found a cheap, non-genuine battery inside, designed to break down after only a few uses. This is definitely a genuine new battery, so there shouldn't be any problems, but just in case, I'm offering it with a warranty (*^^*) I will also include a warranty card, so you can rest assured (*^^*) I offer a free one-week warranty, so please feel at ease (*^^*) Extended long-term warranties are also available, so please feel free to contact me (*^^*) I also accept repair requests, so please feel free to consult with me (*^^*) I appreciate the kind words! Thanks to the overwhelming response, I've received very positive feedback, so I've significantly reduced the price! Please consider it (^-^) ⚠ We do not accept returns for issues such as incompatibility due to version differences, so please make sure to confirm before purchasing m(_ _)m I may be able to accommodate your desired version, so if you have a preference, please feel free to consult with me (^-^) Wireless Noise Canceling Stereo Headset WF-1000XM4 Brand: SONY Wireless Noise Canceling Stereo Headset WF-1000XM4 Brand: SONY Wearing style: Separate left and right, completely independent Earphone/Headphone type: Canal type Structure: Sealed Wireless/Wired connection: Wireless Earphone/Headphone features: Noise canceling, Hi-Res, Microphone, External sound input, Waterproof, splash-proof, Remote control wf-1000xm3 wf-1000xm4 wf-1000xm5 wf-sp900 wf-ls900n wf-l900