This diode has the following specs which are from the NSN number except the overall diameter of this diode is 1" compared to the 1.12" shown below.

• Inclosure Material: Metal
• Overall Length: 0.700 inches maximum
• Overall Diameter: 1.120 inches maximum
• Mounting Method: Threaded stud
• Hermetically sealed case
• Nominal Thread Size: 0.3125 inches
• Semiconductor Material: Silicon
• Voltage Rating in Volts per Characteristic: 600.0 maximum working peak reverse voltage, maximum peak total value and 420.0 maximum reverse voltage, total rms
• Current Rating per Characteristic: 100.00 amperes maximum forward current, dc
• Power Rating per Characteristic: 350.0 watts maximum total power dissipation
• Maximum Operating Temp per Measurement point: 150.0 deg celsius junction
• Unpackaged unit Weight: 90.0 grams
• Thread Series Designator UNC
• Alternate part number: 720621-21
• NSN: 5961-01-209-5010