Saizi: 2.5×2.5cm Power supply: 2.7~5V@30mA Work frequency: 125KHz Support chip: ATA5557, T5567, T5577 or compatible chip (default format Manchester code RF/32) Interface: serial port (TTL-232 format) Verenga chinhambwe: <7cm, write distance: <6cm (T5557, T5567, T5577 Chip R/W Module has read-only and read-write two models, according to the project needs to choose the right module.)