What they say:

Arione is designed for Snake type riders with flexible spines who feel comfortable standing or sitting and changing positions on the bike. R1 uses a carbon-injected nylon twin flex body for lighter weight.

• Wing Flex shell flexes downward where the inner thigh contacts the saddle, allowing more efficient pedaling and full-range of motion
• Carbon Thermoplastic Composite shell with Wing Flex
• Carbon Braided Rail: sleeve of braided carbon fibers filled with unidirectional carbon fibers that are capable of expanding and contracting
• Integrated Clip System: tool-free interface in the saddle base that allows quick attachment and removal of fizik packs and blink lights (ICS is found on all saddles unless noted)