The 12" KB Stainless Steel False Bottom fits 10 gallon Rubbermaid coolers (tightly). It is a very tight fit in a 10-gallon cooler, which means full coverage on the bottom of the cooler, but removing for cleaning is difficult and can scratch the sides of the cooler. Some brewers prefer this size over the 9" false bottom. False bottoms are used to convert coolers or plastic buckets into mash/ lauter tuns. Constructed from 304 stainless steel these false bottoms will not float. Dome height is 1/2" for the 9", 10", and 12" diameter false bottoms. Comes with a 3/8" barbed 90° stainless steel elbow hose fitting in the center to draw the wort from beneath the dome. Made from stainless steel with 3/32 perforated holes on 5/32 centers. The barb fitting is 3/8 ".