First is a false bottom specifically designed for Brew In A Bag process. When you use a mesh bag in a pot, whether it's directly fired on a burner or heated electrically, you want to keep the bag off the bottom. Typical homebrew false bottoms have really small holes and cut off the free flow that mesh bags are know for. Another less desirable choice is a steamer rack or tray that is found in kitchen shops, but none of those are stainless steel.
We've redesigned the support structure by using 1/8" thick, 1/2" wide 304SS flat bar that is rolled into a ring and further supported by an X-shaped cross brace. The legs are made of M8 metric bolts and are threaded into NINE nuts that are welded to the underside of the support structure. This modular leg style allows for just about any height you need just by changing out the length of the bolts. For this particular 17.5" version, the leg attachment points have been increased to a total of 9. It is more than needed so we include six legs that you can install at whatever locations you feel most appropriate. In some cases you'll be leaving a leg out of position so it does not contact your electric heating element or any other low accessory.
You have the choice of several lengths during purchase, selectable in the drop down menu. Note that if you select "no legs", the screen still has the welded nuts that will accept legs in the future. Without the bolt legs, the screen will sit about 1/4" off the bottom supported by the bottom rolled ring. The heights listed in the drop down refer to how much clearance you will get between the bottom of the pot and the bottom of the FB support structure.
IMPORTANT: The leg attachment points are strong enough to support the weight of just about any grain bill you throw at it, along with a reasonable rate of pump-recirculated wort. However, you must use care and evaluate how fast of recirculation your exact bag can handle before it starts clogging with fine particles. It is possible to circulate too quickly and create a hydraulic vacuum underneath that will damage the BIAB false bottom. This warning especially applies to the 17.5 Diameter bottom. Due to the vast surface area, it doesn't take much pump suction to exert a massive force. Please throttle your pumps down a bit, especially if you mill near flour particle sizes.
Again, make no mistake about it. If you see another product like this on any restaurant supply store, amazon or ebay, know that they are all chrome plated steel and they will rust.
Based on listed specs on popular pots, this 17.5" model should fit:
Blichmann G2 20 gallon 17.75"
Megapot 1.2 20 gallon 17.7
Bayou 20 and 25g 18.5"
Spike 20g 17.7"
SS Brewing Technologies 20g 17.7"
Brew Built 22g 17.7"
Of course the fit is not tight, but as long as the bag doesn't have several inches of slack, it should not get pulled down into spaces smaller than 1/2".