Endurance Butterfly Clamps Link Chain. Endurance nipple clamps with link chain offer maximum pressure for an intense and localized experience. These endurance nipple clamps feature a sturdy, durable link chain. Non-piercing body jewelry. For first timers please check every 15 minutes to ensure bruising to delicate tissue does not occur. To turn up the volume use a nipple sensitizers. Spartacus A Passion for Quality Catalog page 11.