Why do I need a conversion kit for a Kitchen Aid 4 Burner Gas Grill - Item # 6702 Model # 720-0745A

My name is Victor on behalf of Nexgrill Industries Inc., the manufacture for grill Model Number. The conversion kit comes with a 10ft gas hose and a natural gas regulator, if you already have pre-existing hose and regulator from a previous grill then you can hook up directly to the gril, however you will still need to change the orifices on the grill, the grill will provide the natural gas orifices needed. Should you need additional product information please feel free to contact us at (800) 913-8999 Monday – Friday 8:00am -5:00pm PST. We have representatives available to assist you with technical support as well as order processing. Thank you for choosing Nexgrill and happy grilling! Victor