If it's silver, it would not have S-C which is normally - at this period - only found on bronze coins, because the emperors needed permission from the Senate to strike bronze coins, which the SC essentially means ("The Senate has been consulted").
There is nothing in
RIC or
BMCRE with just PROVIDENTI
AVG and no
PROVIDENTIA AVG types for Ant. Pius. (I cannot see
COS III at the end of the
obv. legend, I can only see
COS I or possibly
COS II.)
It could be a modern copy using an
obverse from Ant. Pius and the
reverse of, for example,
Carausius, as the lettering does look peculiar and the
quality control was generally excellent during the time of Ant. Pius.