This part is a kind of semiconductor called KBU02.

Function of this product has KBU Series.

Manufacturers : ETC

Image and pinout :

Some of the text within the PDF file :

Type Maximum Maximum Average Peak Rectified Current Reverse @Half-Wave Voltage Resistive Load 60Hz PRV VPK Io@ TA AAV Maximum Forward MaximumReverse Peak Surge Current Current @PRV @8.3ms @25 TA Superimposed IFM(Surge) APK IR µADC Maximum Forward Voltage @25 TA IFM VFM APK VPK [ ... ]

KBU02 PDF Datasheet Download