NTE6356 Power Rectifier Diode 300A 600V, DO9
 
Features:
-Diffused Diode
-High Voltage Ratings up to 1600 Volts
-High Surge Current Capabilities
-Available in Cathode−to−Case (Standard) or Anode−to−Case (Reverse Polarity) Style
 
Full spec sheet:
https://www.nteinc.com/specs/600to699/pdf/nte621.pdf