This is an optional 1.4mm front or rear sway bar for the Kyosho Lazer ZX-5 4WD off-road buggy. This sway bar can be used on either the front or rear of the buggy, and you can use different sway bar thicknesses to adjust the amount of traction at the front or rear of the buggy. The thicker the sway bar, the less the car will roll at that end of the buggy and the less traction it will have. However the less the car rolls, the move corner speed it can carry.
The stock sway bar that comes in the kit is 1.2mm and is only included for the rear.