an outer shell including a first shell and a second shell movable relative to the first shell; levers hingedly connected to the first shell on left and right sides of the sport helmet for adjustably securing the first and second shells together, the levers of the first shell including first members engageable to second members of the second shell, the first and second members defining at least two attachment points each corresponding to a respective one of at least two sizes of the sport helmet, the levers pivotable between an engaged position and a disengaged position, wherein in the engaged position the first shell is secured to the second shell via cooperating engagement of the first members with the second members at a corresponding one of the at least two attachment points, and wherein in the disengaged position the first members are disengaged from the second members such that the first shell is slidably movable relative to the second shell to adjust a size of the sport helmet; and

finger-engageable locking actuators for selectively allowing movement of the levers from the engaged position to the disengaged position, the finger-engageable locking actuators mounted to one of the outer shell and the levers, each one of the finger-engageable locking actuators having a body; the body including at least one anchoring projection protruding away from the body, the anchoring projection displaceable between an extended position and a retracted position receivable within anchoring apertures, the finger-engageable locking actuators movable between a locked position, wherein the anchoring projections are in the extended position and received within corresponding anchoring apertures and an unlocked position, wherein the anchoring projections are in the retracted position, the anchoring apertures defined by another the one of the outer shell and the levers, wherein in the locked position movements of the levers relative to the first shell are limited by the anchoring projections that are received within the anchoring apertures, and wherein in the unlocked position the anchoring projections are disengaged from the anchoring apertures such that the levers are pivotable between the engaged position and the disengaged position.