Fits snug in my replacement shell but overall works great!
It’s a really good battery but with the sticker on the outside it is bigger then then oem and as a result it is a very very tight fit but it did fit
Li-Ion Rechargeable Battery Replacement for Game Boy Advance SP
Li-Ion Rechargeable Battery Replacement for Game Boy Advance SP
Battery works well if you can get it to fit in. Tried putting it in an OEM shell and it would not go in without way more force than should be needed, and if it would have gone in, it would have not come out.
It did fit in the after market shell I bought, however it still was on the tighter side and requires me to pry it out with a screw driver if I need to get it out.
So first issue I had was it did not fit in the casing. I bought a new casing,Pikachu version, on this website and it still didn't fit well unfortunately. Despite charging the battery all the way, it will occasionally switch from green to orange and then after a few minutes back to green again. It worries me since I'll never know if it is actually low. The battery does work though thankfully if you are in dire need of a battery replacement