CAUTION: I've noticed many reviews for this item are for the smaller instant pot. MAKE SURE YOU ARE ORDERING FOR THE LARGE ONE. One is 10" and the other is 9". Drives me nuts when they do that. These were impossible to get for awhile and if you intend to use your instant pot 8 qt cooker as a slow cooker or yogurt maker, you need this if you want to look in on your food without having to remove the lid. Its well made and sturdy and I was unable to find a substitute that fit. Then the price was outrageous and I thought I would have to bite the bullet, but this price was pretty good. I don't use it as often as I thought I would because I'd rather pressure cook than slow-cook, but I intend to make more yogurt eventually so this will make it less of an adventure. So, you don't HAVE to have it, but its comforting to know I have it when needed. .