Improving on perfection is hard, but we found a way to do it with the all-new Iron Flask 24 oz Rover 2.0 Tumbler. This tumbler cup has the same double-wall-insulated, stainless steel construction that keeps your drinks icy for 18 hours and hot for 4 hours and the powder-coated finish you loved with the original Rover, but it now includes a 100% leak-proof design, whether you’re using the flip lid or the straw lid with extra straws. This time we also added a rubber bottom that protects your bottle from dings and acts as a built-in coaster.