This Pokemon Sapphire copy is a little different than the other copies of Pokemon games that Poke Swagg Shop has in stock.
The battery has been replaced on the cartridge but this game is being stubborn. After having a professional go over it we still weren’t able to get it to accept the battery. 
“The internal battery has run dry. The game can be played. However clock based events will no longer occur” 
The battery is for clock based events. So without a working battery that’s the only difference. It will not affect 99.9% of the gameplay. It’s just an awesome way to get the game at a discount!