****Please let us know which Firmware you need****. LEAVE MESSAGE WHEN PURCHASING. Authentic - Refurbished - Replacement Part - NOT A COMPLETE SET - You will receive a single "RIGHT SIDE" replacement item. One original silicon ear tip will be included. Thoroughly tested and guaranteed to operate as intended by the manufacturer. ***The replacement earbud has been updated to FIRMWARE 4.2.1 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.***** ****IF YOU NEED FIRMWARE 4.1.0 LET US KNOW AND WE WILL TRY TO FIND ONE FOR YOU.**** Initialize the headset to restore factory settings. Instructions may be found here: https://www.sony.com/electronics/support/articles/00278109#Initialize Initializing video instructions can also be found on this page. Return Policy: Our 100% Satisfaction Guarantee promises that our products have been tested and fully work. We accept returns up to 30 days from delivery. Items just need to be in their original condition and packaging as received. We will apply a 20% restocking fee for returns if there were no issues with the item or if you changed you mind or didn't like them. If you have any issues, please give us the opportunity to resolve your concern. If the item is defective, non working, or does not match description, please contact us for an easy return.