The DJI Ronin-S Focus Wheel attaches to the Ronin-S handle and allows you to control focus when rotated. It digitally controls focus when using select cameras (as per the Ronin-S camera compatibility list). If an optional remote control receiver is incorporated, the receiver will control the Focus Wheel remotely. The Focus Wheel features a CAN/S-BUS selector switch syncing up to DJI and third-party receivers.