Endurance Butterfly Clamps Jewel Chain Nipple Clamps with jewel chain offer maximum pressure for an intense and localized experience. Endurance nipple clamps with butterfly style tips. These clamps have silicone tips and are specially designed to become tighter as you pull on the jewel chain. These endurance nipple clamps feature a fine, silky jewel 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 like Doc Johnson Novelties makes item number DJ785302. Sold separately.