PokéNav

Is a Key item in Hoenn. In Pokemon Ruby and Sapphire, it is Trainers eyes where you can see their favorite kind of pokemons, etc. and in Pokemon Emerald it is Match Call which allows you to call other trainers.

How To Obtain
R/S/E: Defeat the Team Magma grunt (Ruby)/Team Aqua grunt (Sapphire and Emerald) in Rusturf tunnel.