Need a little help identifying this diode...

I've got three very small diodes that I THINK are ZD39's.  But I want to make sure before I install them.

They are in DO-35 style packaging.  They're very tiny.  I can barely make out the numbers on the side, even with a very potent magnifying glass.  It looks like it says...

25
98

or maybe...

25
9B


I looked at Mouser's website (where I likely would have purchased them) and found no match.  The usual internet searches have been equally inconclusive. 

Help?

..feed them some higher voltage (e.g. 48V) through a 10K resistor, and see if/where they stabilize..?