Strut bar
A strut bar, strut brace, or strut tower brace (STB) is an automotive suspension accessory on a monocoque or unibody chassis to provide extra stiffness between the strut towers. With a MacPherson strut suspension system where the spring and shock absorber combine in one suspension unit, which also replaces the upper control arm, the entire vertical suspension load is transmitted to the top of the vehicle's strut tower.