ASICS Women's GEL-DS Trainer 17 Running Shoe 100% Synthetic and mesh Rubber sole Clutch Collar System A descendant of the Heel Clutching System, an Endoskelatal collar compliments the exoskelatal heel counter for a uniquely secure fit. Guidance Line Vertical flex groove decouples the tooling along the line of progression for enhanced gait efficiency. Propulsion Trusstic