In the cock pit the stop-watch is king. A fast pit stop can mean the difference between celebrating on victory lane or spending the week analyzing what went wrong. Though finances dictate how many people are on a team's pit crew, NASCAR limits both the number of crew members allowed "over the wall" and the tools that can be used. During the first half of a race only seven crew members are allowed over the wall. These seven people must refuel, change tires, and make any repairs or mechanical adjustments that the car needs. And they must do this using only one jack, two gas cans and two impact wrenches. During the second half of the race an additional crew member is allowed to be over the wall, making a total of eight.