The Covidien/Kendall's MEDI-TRACE™ 200 Series ECG monitoring electrodes provide superior adhesion and ease of use for quality adult monitoring. The small, teardrop-shaped electrodes measure 1.5" in diameter for easy lead placement. Great Design - Featuring a low-profile, tear- and fluid-resistant foam substrate backing and conductive adhesive hydrogel, the electrodes are excellent for skin coupling and electrical contact. It's coating on the upper snap is nickel while the snap is nickel-plated bass. The gel is formulated to stay fresh out of the package for 45 days.