Game Boy Advance SP Power Adapter

And it's cheap.

Makes a high-pitched buzz that you might notice in a very quiet room. Also the bumps on the charging head that are used to keep the wire from slipping out of the GameBoy are a little more pronounced than the original charger, which makes putting it in feel like you're putting too much force on it.

Besides that, very good overall. Thanks!

Game Boy Advance SP Power Adapter

Haven't used it a lot yet, but so far it seems to charge as expected. The connector into the GBA SP is a good fit. Quality appears to be decent. It's a little lighter weight than the OEM charger.

I see so many listings online for Gameboy Advance SP's that are without chargers. This solves that and for a reasonable price.