The ALQ2-DMDFB from L-COM is a RF Surge Protector with Frequency 800 to 2250 MHz, Insertion Loss 0.1 dB, Operating Temperature -55 to 155 Degree C, Voltage Level 4000 V(Dielectric Voltage). Tags: Quarter-Wave Shorting Stub (QWS). More details for ALQ2-DMDFB can be seen below.