1. RMF-TX310U RMFTX310U Replacement Voice with Mic fits for Sony 4K Smart Bravia TV. (1. The back cover is designed not sit flush with the other part(means the bottom does not stay flush when closed), it's not defective, it's just the factory design, do not worry. 2. If you feel a little stiff when you receive the remote, do not worry, it is just because it's , no problem with it. it will be soft when you use it for a few days.) 2.Easy to use, firstly install 2 AAA alkaline batteries, then pair it with your TV, then it works. Pairing Method: Hold 'VOL-' button and 'Mic' button for 3 seconds to initiate pairing. Voice remote is one-to-one use, please make sure only our this remote paired with your TV, no other remotes are paired with your TV. 3.Compatible with Sony TV model Bravia XBR-43X800G XBR-75X800G XBR-65X800G XBR-49X800G XBR-55X800G XBR-85X900F XBR-49X900F XBR-75X900F XBR-65X900F XBR-55X900F 4.Bravia XBR-55A8G XBR-55X850F XBR-60X830F XBR-65A8G XBR-65X850F XBR-70X830F XBR-49X850F XBR-75X850F XBR-85X800G XBR-85X850F XBR-85X855F