This is a SONY wireless earphone WF-1000XM5. Only the right earbud (R). I am selling it because I lost the left one. The version is 5.0.2. If you have the left earbud and the case, you can initialize and re-pair it! Recommended for those looking for only the right earbud. 〈How to initialize and re-pair〉 ① Put both the left earbud you received and your right earbud into the case. ② At this time, the case lamp will blink orange 3 times repeatedly, which is a sign of an abnormality in the combination of left and right. ③ Press and hold the button on the back of the case for 15 seconds or more (initialization) while the case is open. ④ The lamp will blink orange. ⑤ Release your finger from the button within 5 seconds. ⑥ The green light will blink 4 times → no light. ⑦ Press and hold the case button for about 5 seconds. ⑧ The lamp will blink blue twice, so re-pair with your device. I haven't measured how long the battery lasts, but I listened to it during my commute (3 hours round trip), and the battery percentage was 80%! (This cannot be guaranteed.)