Does this work with matted dog?

I wouldn’t recommend for matted hair it will pull and get stuck. It works best with straight free flowing hair.

Are there any stainless steel blades available to purchase?

I contacted the company to inquire about buying just the blades. It is important to have extras on hand, especially for multiple dogs- much easier to swap them out and sanitize all at once, and to have one on standby if needed. The company says they only sell the filter combo kits at this time. However, they did acknowledge that it is a good idea especially for the reasons given. I would encourage you to contact the company and also make this request. This is an extremely important accessory and is viewed as a deterrent for anyone who takes this as a necessity! $40. is expensive just for a single extra blade/ let alone if you have 3 or more dogs... Side note: I borrowed the P2 unit but purchased a different more expensive model because of this and the extra paw and nail trimmer on the other brand. Its quality was so poor that I didn't use it for more than 5 minutes before I boxed it up and returned it. We ordered this instead because I love how great it cuts and how much hair it holds! I wasn't able to verify until after purchasing this that the extra blade packs were not yet available. With enough requests the company may soon offer extra blade sets.

Can you buy replacement combs?

Hello, we have the combs to sell. Here is the link: https://www.amazon.com/dp/B0B14M98YR?ref=myi_title_dp Any questions or problems, please feel free to email us via support@neakasa.com

Can I use this on my beaver pet? It gets bushy especially in the winter?

If we are talking about an actual rodent-type beaver, I would say it depends on how oily the fur is. I wouldn't recommend this for wet or oily fur/hair. I think it would clog up the filters and you wouldn't be able to remove caked hair out of the suction pipe as it does not disconnect.