The XN521-I/XN521-II from Sainty-Tech Communications Limited is a RF Switch with Frequency DC to 0.3 GHz, Insertion Loss 1 dB, Isolation 64 dB, Supply Voltage -5 V, Switching Speed 8 nS. Tags: Surface Mount, Solid State. More details for XN521-I/XN521-II can be seen below.