Features: brand new and high quality Small size, low power consumption, high transceiving sensitivity. Support UART interface, and support SPP Bluetooth-compatible serial port protocol. Mainly used in the field of short-distance data wireless transmission. Can be easily connected to the Bluetooth-compatible device of the PC, and can also communicate data between the two modules. Avoid cumbersome cable connections, and can directly replace serial cables. Specifications: Material: PCB for HC-05/06 Operating Frequency Band: 2.4GHz -2.48GHz unlicensed ISM band BT Specification: V2.1+EDR Output Power Class: Class 2 Operating Voltage: 3.3V Host Interface: UART Dimension: 27mm (L) x 13 (for W) mm x 2mm (H)/1.06x0.51x0.08 in Note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1x Module