Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: Is the filter made of stainless steel also, or is it aluminum?
Document: most of parts are made of stainless steel except plastic and rubber, and is also dishwashable.4-cup size is big enough for a whole family coffee time.
This little stainless steel Moka pot has served me well over the past seven months. It makes the same potent brew as the traditional aluminum model, but will not corrode or build up nasty deposits in a short amount of time like the aluminum pots. I feel that in the long term it is well worth the little bit of extra money. I also like the classic minimalist deign.
The espresso maker worked well for what it was intended. However, a negligible amount of steam-drip came from the hole behind the lid lever onto the stove top leaving brown splatters each time I used it (not an issue). Also, and this is the big problem: The product only lasted 1 year of daily use before the bottom rusted out. I'm not sure why this happened as it is suppose to be made of stainless steel.
I used to use an aluminum espresso maker like my relatives in Italy. However, when the handle broke I began looking into other options. I really didn't want another aluminum maker due to the link between cooking with aluminum and Alzheimer's. I love the Bialetti brand and have another of their products. When I saw that this espresso maker was made with stainless steel I jumped at the opportunity to purchase it. I absolutely love love love it.
I wanted a stainless steel espresso maker that was also beautifully designed, and makes great espresso. And this is it! I love it. It is fast and easy to use, and takes less than 5 minutes to make. Be sure that the handle is not over the burner or the flame, and that you throw away your first batch (one time only - not every time you use it), do not clean with soap, water only, and let it air dry afterwards before putting it back together.
I wanted an inexpensive method to make a decent cup of espresso and this is it. The stainless steel is highly polished, the quality of the welds is excellent and the pieces fit together great. It is very easy to use and I love the fact I don't have to use filters.I also purchased an electric milk frother. Using Starbucks Espresso Roast I am able to make Latte's just as good as Starbucks. My eggnog latte is even better than theirs.
We have used stove top espresso coffee makers for many years. This is an excellent stainless steel option for those concerned about aluminum toxicity.
We looked and looked to replace our 1 cup stainless steel espresso maker. This little stove top one is just perfect for everyday use. The aluminum ones just don't cut it.
this is a great and healthy way to have a cup of expresso. The stainless steel is way better than aluminum versions. Each pot makes about 1.5 of my size cups so I am really managing my caffiene intake
What can I say! I am an expresso freak and must have my stovetop pot. I use stainless steel as aluminum can leach into your body. This is my third or fourth Bialetti. I guess that tells you I am happy with it.
Answer: The upper and lower filters are both stainless steel. No aluminum at all in this coffee maker.I have a pot on the stove as we speak!