Description The Gander RV Duel, formerly known as the Twin 125s, is a Monster Energy NASCAR Cup Series preliminary event to the Daytona 500 held annually in February at Daytona International Speedway. It consists of two 150-mile (240 km) races, which both serve as a qualifying race for the Daytona 500. The finishing order in the two 150-mile (240 km) races, held on the Thursday before the Daytona 500, determine the starting lineup for the Daytona 500 held on race day.
Qualifying for the Daytona 500 is unique in NASCAR. Only the two front row starters (the pole and "outside pole") are determined by the standard knockout qualifying system. For all other drivers it only determines their starting position in their duel with odd placed cars being entered into the first duel and even placed cars going in the second. After the Top 2 positions are locked in, the next 30 places of starting grid of the Daytona 500 is set by the finishing order of these two races with the top 15 (excluding pole winner and outside pole) making up the next 15 places on the inside and outside lanes respectively.