The MBP25B from Massachusetts Bay Technologies is a RF PIN Diode with Reverse Voltage 25 V, Series Resistance 0.55 to 0.80 Ohms, Thermal Resistance 50 Degree/W, Capacitance 0.15 pF, Operating Temperature -55 to 150 Degree C. Tags: Chip. More details for MBP25B can be seen below.