Roland WM-1, Wireless MIDI Adapter, Up to 10 m range, Connection to MIDI devices directly at the MIDI In / Out sockets, Latency: 7.5 - 15 ms (standard mode) / 3 ms (fast mode), In standard mode, up to 3 units can be connected to one master., Fast mode and connection to Mac, PC and iOS devices via Roland WM-1D (Art.#504209# - not included), Power supply via AAA battery (max. 60 hours), Dimensions (W x D x H): 79 x 17 x 29 mm, Weight: 46 g