Wireless Battery Transmitter for Built-In with 2 Separate Channels, Used to Send to Yoki's Wireless Receivers: MTV500ER, MTR2000ERP and MVR500ERP.Range up to 250m in free air, range will be reduced by wick, metal and other building parts.Number of receivers per channel is 4 pcs. in direct mode and in radio bus it is unlimited. Battery CR2032.Operating temperature -10 ° C - + 50 ° C.B battery CR2032.The compact built-in transmitters can easily be integrated into the existing installation.