S&M ATF FrameThe ATF bmx frame from S&M is the base model of all of S&M's lastest signature frames. The ATF (Alcohol, tobacco and firearms) uses S&M's standard heat treated supertherm tube set with a tapered and butted top tube for extra strength, dent resistant down tube, tapered rear stays with massive rear tyre clearance and heat treated micro dropouts. S&M says the frame is a bit burlier and stronger than most of their frames but still only weights in a 4.