The Maddy Brand Tote Brush was a very interesting product that I came upon at the Boom Boom Room this year. It's the first ever travel bottle brush, which features a stainless steel telescoping shaft. It reduces down to a size of 5 1/2" x 2" when fully closed and extends out to a length of approximately 8" when opened.
Pretty nifty and it also works on canteens.
