Blackline 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. Nipple clamps can be applied to the nipples of either men or women. They create pain/pleasure by restricting blood flow from erect nipples by applying pressure to them. Most nipple clamps are adjustable allowing the user to determine the amount of pressure. 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 like Doc Johnson Novelties makes item number DJ785302. Spartacus A Passion for Quality Catalog. New images added February 1, 2013.