bycantine coin

Dear all,

I do have here a Bycantine follis,Cu, dia 30 mm, 10 gr.; Anno XX, Officine A, Cross above M

Av is very worn

What puzzles me is the mint, I could nowhere find a Mint CAY or CAV. From style and Year 20 it could be  Justitian I. 

Any suggestions?

Thanks in advance

Heraclius with Heraclius COnstantine, Isaura mint (ISAYR)

https://www.acsearch.info/search.html?id=14494778

A request has been submitted to add it to the catalog.

Many thanks for yout help, I am pleased to cotribute to the catalogue, so please place it and the appropriate position

Byzantine Empire: Heraclius (610-641) Æ Follis, Isaura, RY 8 (Sear 848; DOC II.183)

Obv: Facing busts of Heraclius on left and Heraclius Constantine, smaller on right, each wearing crown with cross, and chlamys; between their heads, cross
Rev: Large M between A/N/N/O and ЧII; above cross; beneath, A; in exergue, ISAYR