This part is a kind of semiconductor called GBU406.

Function of this product has 4.0A GLASS PASSIVATED BRIDGE RECTIFIER.

Manufacturers : Diodes Incorporated

Image and pinout :

Some of the text within the PDF file :

GBU4005 - GBU410 4.0A GLASS PASSIVATED BRIDGE RECTIFIER Features · · · · · · · Glass Passivated Die Construction High Case Dielectric Strength of 1500VRMS Low Reverse Leakage Current Surge Overload Rating to 150A Peak Ideal for Printed Circuit Board Applications Plastic Material: UL Flammability Classification Rating 94V-0 UL Listed Under Recognized Component Index, File Number E94661 GBU Dim A B K C L M Min 21.8 3.5 7.4 1.65 2.25 1.02 4.83 17.5 18.3 3.30 0.46 0.76 Max 22.3 4.1 7.9 2.16 2.75 1.27 5.33 18.0 18.8 3.56 0.56 1.0 A B C D E Mechanical Data · · · · · · · Case: Molded Plastic Terminals: Plated Leads Solderable per MIL-STD-202, Method 208 Polarity: Marked on Body Mounting: Through Hole for #6 Screw Mounting Torque: 5.0 Inch-pounds Maximum Marking: Date Code and T [ ... ]

GBU406 PDF Datasheet Download