Best Rechargeable 9 Volt Battery, Need suggestions

I have a dog color that has a remote controller so I can beep or vibrate the dog. The collar has a built in battery. But, the hand held controller runs a 9 volt. I can put a fresh Energizer in and 3 days later with little to no use, it is dead. So this could get expensive. I thought about wiring a small switch and likely will. But in the mean time, I want some long lasting rechargeable 9 volt batts.
I read the reviews for the collar and saw this was a issue. I have some small switches and will wire one in soon. But does anyone have a suggestion on a good rechargeable? Even after the switch, I want them.

Thanks.

Here is a thread on it.

Yes!!! I just saw that thanks. No need for anyone to reply to this one!

Mods, feel free to delete this!

Thanks.