The CE3521M4 from California Eastern Laboratories is a RF Transistor with Frequency 20 GHz, Power Gain (Gp) 11.9 dB, Noise Figure 0.75 to 1.05 dB, Supply Voltage 1 to 3 V, Voltage - Gate-Source (Vgs) -1.1 to -0.39 Vdc. Tags: Surface Mount. More details for CE3521M4 can be seen below.