The ASR310S2 from Abracon LLC is a SAW Resonator with Frequency 309.925 to 310.075 MHz, Centre Frequency 310 MHz, Insertion Loss 1.5 to 2.5 dB, Capacitance 1.8 to 2.4 pF, Quality Factor Loaded 2000. Tags: Surface Mount, SAW Resonator. More details for ASR310S2 can be seen below.