5 of 5 people found the following review helpful
does exactly what it says,
This review is from: Nintendo DS - Compatible Battery 850mAh - Extra Long Life (Electronics)I purchased this after owning my DS since release. After using it nearly daily all that time, my battary was barely lasting an hour.
My battery life massively improved when I purchased this as a replacement.
Id advise anyone not wanting to buy a DSi to give their old DS a bit more life :)