This part is a kind of semiconductor called K1058.
Function of this product has 2SK1058.
Manufacturers : Renesas Technology
Image and pinout :

Some of the text within the PDF file :
2SK1056, 2SK1057, 2SK1058 Silicon N Channel MOS FET Application Low frequency power amplifier Complementary pair with 2SJ160, 2SJ161 and 2SJ162 Features • Good frequency characteristic • High speed switching • Wide area of safe operation • Enhancement-mode • Good complementary characteristics • Equipped with gate protection diodes • Suitable for audio power amplifier Outline RENESAS Package code: PRSS0004ZE-A (Package name: TO-3P) D G 1 2 3 S REJ03G0906-0200 (Previous: ADE-208-1244) Rev.2.00 Sep 07, 2005 1. Gate 2. Source (Flange) 3. Drain Rev.2.00 Sep 07, 2005 page 1 of 5 2SK1056, 2SK1057, 2SK1058 Absolute Maximum Ratings Item Drain to source voltage 2SK1056 2SK1057 2SK1058 Gate to source voltage Drain current Body to drain diode reverse drain current Channel [ ... ]