.The FCX-08-48MJ81864 is a Frequency Control Device (FCX) manufactured by the company RIVER. This device contains an SMD Crystal Resonator SMD-1210-4P, which provides frequency stability and precise timing. The SMD-1210-4P Crystal Resonator is in the surface mount (SMD) form factor and is compliant with RoHS standards. It features a frequency of 48.000MHz and is 1210 mils square in size.