https://www.st.com/en/radio-frequency-transistors/sd2931-12mr.html
SD2931-12MR | Product - STMicroelectronics
The SD2931-12MR is a gold metallized N-channel MOS field-effect RF power transistor.
12mrproductstmicroelectronics
https://www.12mr-northernlight.org/
12mR US-14 Northern Light
12 metre sailing yacht, 1938
us 1412mrnorthernlight