The U15 from Johanson Technology is a RF Capacitor with Capacitance 0.2 to 180 pF, Dielectric Constant (K) 23 to 12000, Dielectric Strength 2.5 x WVDC, Voltage (WVDC) 50 V, 100 V. Tags: High Q Capacitors, Ceramic Capacitors. More details for U15 can be seen below.