I suspect that /12 is a country-specific addition. Only the type AZB798T is engraved on the top of the unit, while the type AZB798T/12 is noted on the unit label on the back of the unit. This means that the unit is referred to as either the AZB798T or the AZB798T/12.
We have been using our AZB798T/12 every day for 3 years. We are satisfied with the unit.