I ordered four units.  I picked up one at random and took it to work to analyze it.
These look like the Pirelli of surplus!  (They are Italian, and good quality for what they are!)
The PC boards in the case look like thin (but standard) Teflon PC Board, therefore are probably can be
duplicated for ham use, and scaled for other frequencies.

3 db bandwidth is right at 100 MHz, IL is about 4.9 dB.

I plan later to see if I can "snowflake" one down to 2300-2400 for terrestrial rover use..  If I can, I'll publish the
changes.

Here are the results:

S12/S21 (Identical)    Filter Shape & Insertion Loss:

S11   SWR

S22  Return Loss