... 5.Dimension:17.6*16.1*5mm RF Receiver module FC-RF 104KeyfeaturesLow-cost mini-size low power consumption. Crystal-based high performance RFIC. Works ... input, frequency band selection: 0 for reserve , 1 for 433Mhz.SPI_CLKDigital input, SPI Clock input AFSKDigital input, modulation selection: 0 ... input, 0: OFF; 1: ACTIVE. DATA_OUTDigital output, RX data outputGNDGND 433MHz RF Receiver Module FC-RF104