square byzantine with two countermarks

[Nero 30]

Please help me to identify this one with two counter marks on the right and beneath      that look like chi-rho

[Obryzum]

Are you asking that we identify the undertype?  Or the Heraclian countermarks?  I think the undertype is probably an Antiochian follis of Maurice or Focas.  The countermark is a bit difficult because it was struck over the date.  There is a good article with the Heraclian countermarks available online.  Do a search for:

Heraclian countermarks on Byzantine copper coins inseventh-century Syria Byzantine and Modern Greek Studies Vol. 30 No. 1  (2006) 1–27

[Nero 30]

Actually I was asking about both, because I had no ideas at all about this coin, but the info you gave me was alighting thanks a lot Obryzum.