In 2002 a magnetic chicane was added to sector 10 of the main linac to compress electron bunches. The beam is accelerated to the chicane in such a way that when it arrives, the particles in the head of the bunch have a lower energy than those in the back. When the particles travel through the curved trajectories of the chicane, the high energy particles take a shorter path and catch up to particles in the head, compressing the bunch. Since magnets deflect electrons and positrons in opposite directions, FACET will upgrade the chicane by adding additional magnets, providing a compressed positron bunches for the first time.