The DR1-3100 from ECS Inc. International is a SAW Resonator with Frequency 309.9 to 310.1 MHz, Centre Frequency 310 MHz, Insertion Loss 2 dB, Capacitance 2.2 to 2.5 pF, Quality Factor Loaded 2100 Q. Tags: Drop In, SAW Resonator. More details for DR1-3100 can be seen below.