This part is a kind of semiconductor called SF15.

Function of this product has 1.0 Amp Super Fast Rectifier 50 to 400 Volts.

Manufacturers : Micro Commercial Components

Image and pinout :

Some of the text within the PDF file :

MCC Features High reliability High current capability Low forward voltage drop High surge capability
  omponents 21201 Itasca Street Chatsworth    !"# $ %    !"# SF11 THRU SF16 1.0 Amp Super Fast Rectifier 50 to 400 Volts DO-41 • • • • Maximum Ratings • • • Operating Temperature: -55°C to +125 °C Storage Temperature: -55°C to +150 °C For capacitive load, derate current by 20% Maximum Recurrent Peak Reverse Voltage 50V 100V 150V 200V 300V 400V Maximum RMS Voltage 35V 70V 105V 140V 210V 280V Maximum DC Blocking Voltage 50V 100V 150V 200V 300V 400V MCC Part Number SF11 SF12 SF13 SF14 SF15 SF16 D Electrical Characteristics @ 25° C Unless Otherwise Specified Average Forward IF(AV) 1.0A TC = 55°C Current Peak Forwar [ ... ]

SF15 PDF Datasheet Download