This part is a kind of semiconductor called 2N3055ESMD.

Function of this product has Bipolar NPN Device.

Manufacturers : Semelab Plc

Image and pinout :

Some of the text within the PDF file :

( DataSheet : ) 2N3055ESMD Dimensions in mm (inches). 0.89 (0.035) min. 3.70 (0.146) 3.41 (0.134) 3.70 (0.146) 3.41 (0.134) 3.60 (0.142) Max. 4.14 (0.163) 3.84 (0.151) Bipolar NPN Device in a Hermetically sealed Ceramic Surface Mount Package for High Reliability Applications 1 3 0.76 (0.030) min. 16.02 (0.631) 15.73 (0.619) Bipolar NPN Device. VCEO = 60V IC = 15A 10.69 (0.421) 10.39 (0.409) 2 9.67 (0.381) 9.38 (0.369) 11.58 (0.456) 11.28 (0.444) 0.50 (0.020) 0.26 (0.010) All Semelab hermetically sealed products can be processed in accordance with the requirements of BS, CECC and JAN, JANTX, JANTXV and JANS specifications SMD1 (TO276AB) PINOUTS 1 – Base 2 – Collector 3 – Emitter Parameter VCEO* IC(CONT) hFE ft PD Test Conditions Min. Typ. Max. 6 [ ... ]

2N3055ESMD PDF Datasheet Download