The HBM-2R3-J308FRNJ5171 from Jinzhou Kaimei Power is a Supercapacitor with Capacitance 3000000 mF, Voltage Rating 2.3 V, Equivalent Series Resistance 10.8 mOhms, Temperature Operating Range -25 to 60 Degree C. Tags: Surface Mount. More details for HBM-2R3-J308FRNJ5171 can be seen below.