Minoura Action Advantage Rollers Trainer Action advantage roller trainer with 80-Millimeter diameter alloy roller drums for natural resistance Lightweight, foldable alloy frame is very portable and offers great stability Adjustable frame compatible with 24-Inch/650c to 27-Inch/700c wheels Foot step, front guard, and additional magnetic resistance unit available but sold separately 1 Year warranty covers roller drum, 5 Year warranty covers frame