The 500L18S2R0XG4 from Johanson Technology is a RF Capacitor with Capacitance 0.5 to 2 pF, Frequency 100 to 2000 MHz, Dielectric Strength 2.5 x WVDC, Voltage (WVDC) 50 V. Tags: Trimmer Capacitors, Ceramic Capacitors. More details for 500L18S2R0XG4 can be seen below.