At Sixt, we like to give our customers as much choice as we can. That's why, when you book with us, you'll be given the opportunity to tailor your rental package more towards your personal needs with a range of optional, additional extras. These extras include child safety seats, Sat Navs, unlimited mileage and additional driver options, to name a few. Just choose the extras you would like when you make your booking. Please note, we d not guarantee the availability of any specific make or model of vehicle, but one within your chosen category.