Dimensions would have been helpful.
7 mm H, 4 mm W & D.

7,3 x 4,2 x 4,7 mm
The Siemens type was "B 45 181"

My guess(tm) is Tantalum.

Yes.
There was an odd old rule "3 Ohm / Volt"
for minimal impendance to drive normal
tantals.
These claimed to be "schaltfest",
somewhat better quality.

MfG JRD