Infusions are temporary magical items that the artificer creates, able to sustain as many as six at once by the late game. Some of these can be pre-existing magic items, while other options remain unique to the artificer. While all are good, there some Infusion notably more effective than others.
One of the limitations 5e places upon spellcasters to curtail their power is Concentration. Aside from preventing a character from having dozens of spells going at once, Concentration spells risk being lost every time their caster is damaged, ending their effect and wasting the spell slot.
With the Mind Sharpener Infusion, a spellcaster can simply use their reaction to succeed on any Concentration saving throw they fail. A Mind Sharpener makes spellcasting more certain, helping the game's most powerful spells go even further.