Diameter: 45cm This sturdy frame utilizes ultra-super duralumin, a material that is about half the weight of titanium but possesses the strength of titanium. The titanium bolt section features an air intake function achieved through difficult long-hole processing, ensuring a smooth release. All parts are machine-cut, and by reviewing the parts to match the frame size, we have established the frame's strength while maintaining its lightness. - Color: Red - Shape: Circular, 4-piece construction The item has seen little use and is in good condition. Please consider this a used item. Thank you for viewing.