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

Input:
Question: What is that "knob" that shows at the bottom of the pot? I do not see it on any other brand cooker..
Document: Thanks, Mom!!) It did a great job on the artichokes, and could cook 2 good-sized ones at once, with some creative packing, but I had to be careful with the pot roasts. If I didn't watch the placement, the microwaves would get through the plastic wall and over-cook one part of the meat, usually the piece at the bottom.
The second time I place the pot in the microway the pressure button blew out of the top. The microwave was fine but the cooker is no longer a pressure cooker, just an expensive microway bowl. Dont waste your money
I just got my cooker.put 1 cup of water. Put in microwave 6 minutes to test it.. it blew the red regulator off and the little round thing fell apart in the pot.any reason why.sorta scared of it now.
I used to own one perhaps 20 years ago and misplaced it in a move or two...I kept looking for it (didn't recall the brand, just typed in "microwave pressure cooker" into Google, Amazon, etc.) and I couldn't find it for the longest time.Then, this past year, it popped up on (my hero):-) Amazon.
Although the Tender Cooker is a little expensive, I love it and would buy it again. In fact, I've purchased 3 other ones I've given as gifts. It is very easy to use, only one pot to clean, and it is the perfect size for a small family, say, of not more than four.
(Wow, has the price gone up on this!! )I grew up eating food prepared in a pressure cooker at least twice a month, so I Need one in my kitchen! When my best electric one bit the dust, I decided to try the microwave one. I did my research (pre-internet!!) and picked this model.I loved it, for the most part. I used it mainly for cooking artichokes and pot roasts.
I just received my tender cooker made by Nordic Ware yesterday 08-16-2011. I was exicted about the idea of it and used it today to cook some turnip greens with a little ham to see  how tender they would get in 30 minutes. They came out great, but the metal ring attached to the top of the cooker came off and the glue they use to hold it appears to be little more than the glue that you use hold stickers or labels on.
I give this cooker 2 stars based upon ease of use and usefulness. I use my cooker for steaming solely vegetables, though infrequently now. Potential buyers should note that my advice may warrant a more generous review for pressure cooking meats. I have NOT attempted to pressure cook meats.The cooker has three parts: the cooker bottom and lid, the pressure weight, and the gasket. This cooker workers. Be advised IMO that this is a labor intensive approach. The cooker is subject to immediate food staining.
I have this gadget for less than a week and I already felt the need to talk about it. I love Nordic Ware products because it is a quality brand that is made in the USA. Being a single guy who occasionally cooks and loves low hassle quick things, I immediately gravitate towards their microwave gadgets. Skimming their products on Amazon, I came across this. I never owned a pressure cooker but new that it tends to cook things quickly. Seeing all the great reviews, I jumped on it.
Love this thing. Good to see they are available again. I bought my first one in the 80's when Costco carried them. You can put all your veggies and a whole chicken in it and in 20 minutes, you have perfection.great seller - fast shipping.
Answer: that is the "feet" of the cooker although they don't look that way in the picture.