There are a few design details that Arai bakes into all its helmets, and they're all present here.

Round exterior head shape.
Known as the R75 concept, Arai very consciously refrains from contours in the outer shell of its helmets that violate the 75-degree -radius rule. Why? Because hard edges could catch on pavement when the helmet is sliding down the road at highway speeds. By maintaining R75, the helmet has a better chance of glancing off objects safely. 

Kevlar reinforcement.
Ever seen a helmet that's been laid down at speed? Pavement makes for a hell of a belt sander. Arai anticipates this and incorporates an internal belt of abrasion-resistant Kevlar inside the fiberglass shell of every helmet it makes to provide added impact/puncture and resistance to being sawed through by passing asphalt.

Exterior shield pods.
Following with Arai's focus on keeping a round-as-possible exterior shape, and with prioritizing energy absorption over all else, Arai's telltale exterior shield pods exist to elimiate the need to carve into the spherical integrity of the helmet. This design both allows for more EPS liner between the wearer and the road, and allows for the helmet to better glance off passing objects.

Shell integrity.
Notice that all Arai helmets forgo the classic vents drilled directly through the "forehead" of the helmet. Instead, Arai builds intake ports directly into its face shields.

All SNELL all the time.
Also see, "no drop-down sun visors, ever". Because this would violate the Snell safety standards that Arai is so dedicated to (having a void between the shell and EPS liner to house a sun visor is an automatic disqualification for the Snell standard.)

*Custom fit.
Last but certainly not least, Arai is the only company offering multiple interior-fit shapes to better address the infinite variety of riders’ head shapes and sizes. In addition to customizable cheek pads and head liners, Arais various models EPS liners are shaped differently to accomodate the natural variation in peoples' head shapes.

Besides the Corsair-X top, Arai’s other “Intermediate-Oval” helmets include the Contour-X and the Regent-X.

If you have a "Long Oval” head shape, the Signet-X is the only game in town. And if you've got a  more round-oval headshape, the Quantum-X has the same exterior shell of the Signet, but the inside EPS is shaped specifically for your cantelope.

It doesn't matter how much you like the looks or features of any given helmet—fit should always be the first and foremost consideration. Within any given helmet model there are aftermarket cheek pads and central liners to help fine-tune fit, if needed.