Check the listing for details. Sony WF-1000XM4 Replacement Earbuds - Left Or Right Headphones--FIRMWARE 2.0.1. Color: Black, Condition: Open box. Listed at 51.99 USD. Sony WF-1000XM4 Replacement Earbuds - Left Or Right Headphones--FIRMWARE 2.0.1 You will receive a single replacement item of your choosing. One original foam ear tip will be included. Thoroughly tested and guaranteed to operate. ***This replacement earbud has been updated to FIRMWARE 2.0.1 and will ONLY sync with an earbud that has the same FIRMWARE. any problem,please contact me,please see a vedio on youtube how to reset the headphones The replacement earbud has been updated to FIRMWARE 2.0.1 and will ONLY sync with an earbud that has the same FIRMWARE. PLEASE LET US KNOW IF YOU NEED ASSISTANCE BEFORE YOU PURCHASE OUR EARBUD. Initializing the headset to restore factory settingsIf the headset does not operate correctly even after resetting, initialize the headset. Place the headset in the charging case, leave the lid of the charging case open and wait for lights to flash repeatedly (red) in sets of 3, then hold your fingers to the touch sensors on both the left and right units for about 10 seconds. Release your fingers when the indicators (red) of the headset start flashing red at a slower pace. The indicators (green) flash 4 times ( ), and the headset is initialized. This operation resets the headset to the factory settings and deletes all pairing information. In this case, delete the pairing information for the headset from the device and then pair them again. Includes： 1* Earbuds you choose