No Photo would be needed now. i am sure now it is a regulator.
If you study link below, it is evident that there are many devices in the same series
**broken link removed**
looking at the pattern, it is nothing but 5V regulator for positive voltages.
you can safely apply + 9 to +12V DEC at pins 1and pon2 (middle-common)
and you would get 5V DC at pin3 with ref to pin2. regarding current carrying capacity, if the the centre TAB is thick, it might take 1 amp load with tab mounted on a good heat sink
if the TAB is a thin sheet of copper, perhaps it could be 500mA version.