The ME91BK01 is a Bluetooth adapter built using the MS50SFA-nRF52832 module. It can be switched between master and slave modes by pressing and holding the button for 2 seconds or using a command. Master and slave modes cannot operate simultaneously, and only one-to-one connections are possible. The device defaults to master mode. In master mode, commands can be used to scan and connect to devices. Scanning can filter by broadcast name and MAC address to identify relevant devices. Connections can only be initiated by specifying a MAC address. The device communicates with the MCU via the UART interface. In command mode, commands can be sent via the UART to modify the scan interval, scan timeout, connection interval, broadcast interval, custom broadcast data, baud rate, and more. It can be used for developing and testing Nordic-based wireless solutions. Model: ME91BK01 Dimensions: 50 x 24 x 105mm Weight: 9.2g Power Supply: USB (DC5V1A) Installation: Connect via a computer's standard Type-A USB port Operating Temperature: -20°C to 55°C Color: White Material: plastic Package Contents: 1 * Adapter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.