Cardinal Health Kendall Medi-Trace™ SF450 Series Foam EKG Electrodes (ES82650) - For STRESS and HOLTER Applications and for DIAPHORETIC Patient Requirements. MEDI-TRACETM SF450 electrodes are intended for use in general adult monitoring applications. The foam substrate repels fluids and conforms to body contours. The patented conductive adhesive hydrogel is designed to stay fresh up to 45 days out of the package. There is a skin abrader conveniently located on the backside. Size: 1-3/4" diameter. 50/BG, 10BG/BX, 4BX/CS. Price per Bag.