Authentic - Open box - Replacement Part - NOT A COMPLETE SET - You will receive a single LEFT side replacement. One original foam ear tip will be included. Thoroughly tested and guaranteed to operate as intended by the manufacturer. All replacement parts come with the latest update. ***This replacement earbud has been updated to FIRMWARE 4.0.2 and will ONLY sync with a right side that has the same FIRMWARE. PLEASE LET US KNOW IF YOU NEED ASSISTANCE BEFORE YOU PURCHASE OUR EARBUD.***** Initializing instructions: https://www.sony.com/electronics/support/articles/00298373 Initializing video: https://www.youtube.com/watch?v=5Ksn4LiuswQ 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.