What it does: Any Pokémon holding Exp Freeze will not receive any experience points from battling.
Where to get it: Found after beating Articuno in battle; small percentage to find it.
If the Exp Freeze is given to a starter/training Pokémon and the Exp Share is given to other roster Pokémon, the exp from battles will be shared amongst any Pokémon holding Exp Share. For example, if you have 1 Pokemon holding Exp Share, it will gain 100% of the battles exp. If you have 2 Pokémon holding Exp Share, they will each gain 50% of the battles total exp etc etc. It is a very effective method to train lower levels in your roster if you have 1 higher level training Pokémon.