All of our jewelry is Hypoallergenic, Lead free, and Nickel free. Made with Sterling Silver 925 American owned small business How to use climbers: You should apply a little force, and squeeze the earrings pins with your earlobe when you use them just enough to make them fit snug, but still comfortably. Climber size is 2.1 x 0.8 x 0.1 cm. 925 Sterling Silver heartbeat climber earrings. They have a matte finish, are high-quality, and very precious. This EKG wave design was designed to mimic the EKG wave of a healthy heart, and it was co-designed by a doctor. They would be perfect for your loved ones, nurses, or medical professionals. Also available in Rose Gold over Sterling Silver and 14k Gold over Sterling Silver. All of our jewelry is Hypoallergenic, Lead free, and Nickel free.