Claudius. A.D. 41-54. AE as (32.0 mm, 18.09 g, 7 h). Rome mint, struck A.D. 41-42. TI CLAVDIVS CAESAR AVG P M TR P IMP, bare head left / S-C, Minerva standing right holding spear and shield. RIC 100; BMCRE 149. aVF. Rare pattern coin.
The heaviest example known of an As of Claudius. It is indeed struck and on a larger than normal flan at 32 mm x 30 mm. David Sear has suggested that this may be a "pattern coin". A pattern coin is a coin which has not been approved for general circulation, produced for the purpose of evaluating a proposed coin design. They are often off-metal strikes, to proof standard or piedforts.