Artificer armour is built by master craftsmen and offers even greater protection than a normal suit of Space Marine power armour. It may be taken as an upgrade for a model wearing power armour and increases the armour's save to 2+. Note that, although this armour gives the same protection as Terminator armour, items that are 'Terminators only' cannot be used with it.
Artificer Armour
Source: Codex: Space Marines, p. 34