Roland WM-1D Low-Latency Wireless MIDI Dongle, Windows CompatibleUSB dongle provides wireless MIDI for Windows computers Also brings Fast mode support to iOS devices and Mac computers in a WM system* Provides low latency MIDI communication between other WM series units and macOS iOS Bluetooth MIDI devices Fast mode delivers ultra low latency communication (3 ms) for timing critical applications Standard mode supports up to four total devices; Fast mode supports two total devices** Powered via USB connection