The extender just allows another level of control, and it stows neatly and discretely around the base of the glass bowl when not in use (nice design).I like the Big Boss, but in the winter I go back to using my oven because I like having the space and enjoy the heat and smells rolling out of my kitchen. One of the features I like is the metal extender that allows you to control how close your food is to the heat source because the foods on top brown much faster than the foods on the bottom.
It is a wonderful tool for preparing low fat vegan foods (seasoned French fries), high fat vegan foods (seasoned French Fries tossed in olive oil), and really amazing steaks (we usually sear thick steaks in a hot cast iron skillet with butter then finish in the Big Boss). We've had this for about a year and half and we really enjoy it. This thing is in constant use during the summer because we live in the desert and naturally avoid firing up the oven (but, hey, come winter- we don't shovel sunshine and heat, right?). and took the time to learn how to use it. I am glad I was not put off by all the negative feedback and went ahead and purchased this. as i type I have chicken and mixed veggies cooking. once you get the hang of it you will hardly ever use your stove again. instead of just writing bad reviews the 1st time you used it because you dont know how I recommend using it leaning how to recook foods. just by learning how long each thing must cook. yes it does require timing it but what meal doesnt? I made pork chops with red potatoes and onions, broccoli and cheese and rolls all at the same time. while cooking the chicken on one rack I can put the other rack in and cook veggies and bread on it. I have made steak (which my husband said was better then he has ever tasted) pork chops, air fried chicken and baked ck breast. what I have found with this is that I can cook a 3 course meal for 2 people in this one bowl. Well that is true for frying in a pan also to cook evenly in a fry pan it has to be in a single layer. the complaints were its not like the picture you cant stack food in it. But never owning a fancy $400 air fryer I fell in love with this one. I debated about it because of the negative reviews.