Note: THIS COIN IS PART OF THE CODED EQVITI SERIES (see the letter "I" in right field which is the 6th lettter in the 6-letter EQVITI phrase. This coin was struck by the 6th officina, i.e. officina "VI"; there were 6 officinae at Ticinum mint at that time; each one struck a different reverse with a different letter from the EQVITI code). For more information about the (A)EQVITI series see the below excellent article by Gert Boersema:
http://www.oudgeld.com/webbib/translation_codewords.htm
Rare and desirable obverse legend with INVICT[vs] title!
OBVERSE: VIRTVS PROBI INVICTI AVG
REVERSE: SECVRIT PERP
BUST TYPE: E1 = radiate, helmeted and cuirassed bust left, holding spear and shield
FIELD / EXERGUE MARKS: -/I//VIXXI
