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Raises accuracy by 20% if the holder moves after the target.
Zoom Lens only becomes a viable item on slow Pokemon whose movesets consists of multiple moves with low accuracy. Though these Pokemon aren't very common, there is at least one who can make use of this item: Gardevoir. Gardevoir's double status strategy, coupled with its moderately low base 80 Speed stat, makes the accuracy boost Zoom Lens provides very appealing.
Zoom Lens will always be compared to Wide Lens, due to their similar effects. While Wide Lens is the better choice on faster Pokemon, those who are naturally slow will find Zoom Lens's 20% accuracy more appealing than Wide Lens's 10%. Neither of these items guarantee a move hits 100%, though, nor do they provide recovery, like Leftovers, or increase sweeping potential like Life Orb or the Choice items.