This brush is designed specifically for cleaning carboys (water jugs). works equally well on 3, 5, and 6 gallon sizes. This brush has the maximum amount of bristles that will fit into these particular glass bottle openings. Its L shape makes cleaning under the shoulders possible. This brush is also well suited for cleaning open fermentation vessels as well. Its bushy bristle end makes cleaning the bottom corners of these vessels easier. Total length is 26.