(This article was submitted by BREWHA customer Harold from Chicago, IL.)
This addition to the Large BIAC (and maybe other sized BIAC's) is a key piece of equipment I think. Especially if you brew higher gravity hoppy IPA's with lots of trub. It allows you to drain the beer from above the trub level (as compared to the level of the racking port outlet level which may be below the trub) and rotate the arm down until you reach the level of trub. I mostly brew high gravity IPA's and it was a problem for me until I got this racking arm.