The utility model comprises a double helix filament body and filament pins integrally arranged on both ends of the filament body, the filament pins are respectively straight line filament pins.

Even with XMM-Newton's sensitivity, the discovery was only possible because the filament is along the line of sight, concentrating the emission from the entire filament in a small region of the sky.

This article discusses about the process and technical characters of direct spinning line of polyester filament in large capacities and analyzes the main factors that impair the production.