Mitsubishi RD100HHF1C RF MosFET, N Ch 12.5v 100W 30MHz, Gain 11.5dB Ceramic.  These transistors are suitable for both non linear FM and Linear SSB type modes up to 50MHz by adjusting the bias voltage.

The original suffix number has been changed from RD100HHF1-101 to RD100HHF1C-501 but both are the same devices only the part number suffix and manufacturing generation has changed.

For further information please see the Mitsubishi RD100HHF1C-501 Data sheet

PLEASE NOTE: THESE ARE GENUINE MITSUBISHI MANUFACTURED IN JAPAN