This is a five pack of genuine Kangertech dual bottom coils for Kanger Aerotank, Protank 3, Mini Protank 3, EVOD 2, and T3D Tanks. This comes with five pieces in one box, in the following resistance levels: 1.5 Ohms or 2.0 Ohms. We recommend changing coils every 2-3 weeks to keep the flavor in your tank fresh and the vapor consistently strong, or every week for heavy vaporizer users (high voltage / high wattage / high vegetable glycerin liquid users). There are five pieces per box.