The Large dual battery kit is for boats, cars, 4WDs, trucks, Vans, RVs, or general automotive & marine applications. The True® 140 Amp Voltage Sensitive Relay offers Priority charging for your Primary/starting battery, Can be used with Alternators with outputs up to 150 amps, The True Dual Lithium battery kit offers fully automatic battery management, it's a Easy to install kit with a wiring diagram Waterproof cables, shockproof, casing, and heat resistant cables for safe and efficient use of the auxiliary battery system. Everything needed to connect a second battery located as far as 20 feet from the primary battery. Includes: 1 True® Smart Battery Isolator with mounting screws. 20 feet #6 high flex red cable with tinned copper cable lugs. 3 feet #6 high flex black cable with tinned copper cable lugs. 2 positive brass alloy battery terminal ends. 2 negative brass alloy battery terminal end. 3 loose crimp on tinned copper cable lugs. 4 sections of adhesive lined shrink tube. 5 zip ties. 1 installation instructions booklet. This product comes packed in a heavyweight zip bag for installer/consumer use.