40D battery on ebay

[Sponge]

I'm looking for a spare battery for my Canon 40D and I'd like some opinions on this listing please:

Original Genuine Canon BP-511A BP511A battery 30D 20D on eBay, also, For Canon, Digital Camera Batteries, Photography (end time 14-Sep-08 17:32:27 BST)

It strikes me as somewhat contradictory. It says 'original genuine canon' but also says 'non oem...replacement'.

I suppose 'non oem' could mean it's a packaged, retail product, but the rest of the description makes me think it could also mean it's a compatable product.

I emailed the seller and he said, 'Hello, this is the Canon BP-511A. And it is the original Canon Battery.

Don't worry. Thanks.'

But I'm still not convinced.