These battery crossover cables are for parallel connections, sold as a set of two (one positive and one negative). Each cable has a 3/8 inch copper battery eyelet and sealed with thick wall heat shrink. These 4 Gauge 24 inch Battery Crossover Cables are TPE (Class K flexible wire). TPEs are tough, flexible, weather and oil resistant. Double insulated braided wire. This cable is more flexible than your typical battery cable, making it perfect for installing crossover cables in battery boxes.