This part is a kind of semiconductor called AM1214-100.

Function of this product has L-BAND RADAR APPLICATIONS RF & MICROWAVE TRANSISTORS.

Manufacturers : STMicroelectronics

Image and pinout :

Some of the text within the PDF file :

AM1214-100 RF & MICROWAVE TRANSISTORS L-BAND RADAR APPLICATIONS . . . . . . . PRELIMINARY DATA REFRACTORY/GOLD METALLIZATION EMITTER SITE BALLASTED LOW THERMAL RESISTANCE INPUT/OUTPUT MATCHING OVERLAY GEOMETRY METAL/CERAMIC HERMETIC PACKAGE POUT = 100 W MIN. WITH 6.0 dB GAIN .400 x .500 2LFL (S038) hermetically sealed ORDER CODE AM1214-100 BRANDING 1214-100 DESCRIPTION The AM1214-100 device is a high power Class C transistor specifically designed for L-Band Radar pulsed driver applications. This device is capable of operation over a wide range of pulse widths, duty cycles, and temperatures and is capable of withstanding 3:1 output VSWR at rated RF conditions. Low RF thermal resistance and computerized automatic wire bonding techniques ensure high reliability and product consistency. A [ ... ]

AM1214-100 PDF Datasheet Download