Vivi Audio&reg; For XBox 360 S 360 Slim 4GB 250GB RF Receiver Power Button Ring Assembly Board Model:Xbox 360 Slim. If your controllers are not syncing to your XBox 360, this part is what needs to be replaced!! This part is for the XBox 360 SLIM (4G & 250G models). It will "not" work on the XBox 360 fat models. Package include:1 x RF Board.