An 85W with magsafe 1. Any of the 60W-85W with magsafe 1 will work but the bigger it is the faster it'll charge. Just make sure you avoid magsafe 2 or you will need an adapter.
Pretty sure that kind of adapter doesn't exist if I'm not mistaken. You can get an adapter for the opposite (plugging an original MagSafe adapter into a computer that uses MagSafe 2) though.
Pretty sure that kind of adapter doesn't exist if I'm not mistaken. You can get an adapter for the opposite (plugging an original MagSafe adapter into a computer that uses MagSafe 2) though.