Assault Vest

Boosts Sp.Def, but bans status moves. (Hold)

Assault Vest gives your Pokémon a 50% boost to Special Defense, but you can't use any status moves while holding it! No Protect, no stat boosts, no status moves at all. It sounds restrictive, but on the right Pokémon it turns them into special tanks.

This item shines on Pokémon that already have good physical bulk and just need help on the special side. It's also great on offensive Pokémon that don't need status moves anyway since they're just there to hit hard. The restriction forces you to go all-in on attacking, which honestly makes teambuilding decisions easier sometimes.