Help with replacement battery for dv6-6170us

Looking into getting a replacement battery for my HP Pavilion dv6-6170us. Came across the HP 12-cell Multi-charge Extended Battery which for some reason actually runs significantly cheaper than the 6-cell Battery on HP Academy. Anyone had any experience with the 12-cell extended battery?

Also, has anyone tried MU09 Long Life Notebook Battery? It's the most expensive of the four options I have, but the reviews seem pretty positive.

 

Some extend batteries will raise the back-end of your laptop so watch out. There is a downside should you want to lay on flat surface. If you can live with that then go for it but if you want same as your old battery I say go to either eBay or Amazon and match it with your original batter part number to find a match and see if those voltage and current specs matches you and have a good warranty and then go with that as well. I ordered new 6-cell for my DVD4-1225dx from eBay and it works just fine batteries will degrade over time 6 or 12-cell doesn't matter I would say save the money if you don't need to run off the battery a lot and use it toward upgrade your RAM instead.