The NXP MRF101BN is an LDMOS RF power transistor rated for 115 W output across 1.8 MHz to 250 MHz. It's built for the HF-to-VHF band — think broadcast transmitters, ISM generators, and amateur radio power amplifiers. The 21.1 dB gain at 100 mA test current means a modest driver stage can push it to full output. The 133 V drain rating gives headroom for 50 V supply designs.
It comes in a TO-220-3 package. The tab is the drain.