What is the best Liner to use for Replacement?? HELP!

I am trying to find out what the best liner is to use for a replacement liner. What gauge do I use? I have seen .006 to .018 for sale. I need 33 feet total. Is it best to buy the kit?? I think from looking around that it is. Any suggestions??
I have seen so many, I think they are all the same.

Thanks,
Dan

Its an old house, I got up and looked down the chimney and its falling apart inside. It measures about 8" inside.. I think I need a 5 or 6" pipe. I have a gas insert that I want to put inside the fireplace. Top Vent. I did find a couple of good deals, but they look the same to me. I saw fireflex, pythonflex and a company out of Canada. The pythonflex price seems to be the best one so far. Has anyone ever heard of Python Flex?? Here is a link to it. Am I allowed to show where I am going to buy it?
http://www.globalchimney.us/chimney-liners/pythonflex-316ti-stainless-steel-chimney-liner-006/

I dont see any clamps here, How do you make sure its not going to slip off??

Dan

I've had great luck with Rockford Chimney, http://www.chimneylinerinc.com/
They will answer any idiotic question you may come up with, patiently. Ask me how I know...

I think the question was, was size is the outlet on your stove?

Olympia chimney liner is the best hands down. its 24g 316SS. Their chimney as long as its the 316 SS is life time waranty even with coal. Yes life time not prorated after 10 years. Olympia is the only company with this kind of quality. Look them up they are located in Scranton Pennsylvania.

Sorry I have a habit of reading the headline and not all the posts. Agreed that SS is not necessary. But if you want SS get Olympia. And no I dont work for them I just really like their product.