The SA1-NMF-1-3G-SK from Xiamen HDG Telecom Equipments is a RF Surge Protector with Frequency DC to 3 GHz, Insertion Loss 0.2 dB, Operating Temperature -40 to 85 Degree C, Surge Current 20KA(8/20 µs). Tags: Gas Discharge Tube. More details for SA1-NMF-1-3G-SK can be seen below.