If you like your cycling tech landmarks, it was 2011 when the first aero road helmet appeared, and even that was a clip-on shell on Mark Cavendish’s regular lid as the Manx Missile sprinted to victory at the World Road Race Championships.

The idea soon caught on and manufacturers began developing dedicated aero helmets for regular raceday use, rather than specialist options purely for time trialling. The trouble with the early aero lids, though, was the improved aerodynamics almost always came at the expense of ventilation, comfort and weight.

Kask first tried to solve those issues with the introduction of the Infinity, with a sliding top panel which retracted to expose a row of vents, giving the rider an option for more ventilation when the need for cooling outweighed need to go fast. But it was still a fairly specialist helmet, and that’s where the Protone comes in, it’s a semi-aero lid which fills the gap between the Infinity and the Mojito, Kask’s lightweight, fully-ventilated climbing helmet.

RCUK100 - Kask Protone helmet

RCUK100 - Kask Protone helmet

RCUK100 - Kask Protone helmet, shell

RCUK100 - Kask Protone helmet

RCUK100 - Kask Protone helmet, shell

RCUK100 - Kask Protone helmet, vents

RCUK100 - Kask Protone helmet

RCUK100 - Kask Protone helmet, vents

The Protone quickly became a favourite with Team Sky because it's a far more day-to-day ready helmet than the all-out aero Infinity

The Protone strikes a balance between aerodynamics, comfort ventilation and low weight in a similar vein to Giro’s Synthe. It’s why the Protone quickly became the aero road helmet of choice for Team Sky’s riders as, while it may not be as aerodynamic as the Infinity, marginal gains also extend to comfort and the Protone is a far more day-to-day ready option. In fact, the Protone was developed in conjunction with Team Sky.

It’s a helmet with a split personality, having five large and three small vents on the front, while the top remains smooth, and the back has a number of exhaust vents to provide an escape route for the air that enters the front.

Besides aerodynamics and ventilation, the Protone uses Kask’s excellent and highly adjustable Octo fit system, and the leather chin strap is the kind of smart finishing touch you expect from a £175 helmet. It’s light, too, at 215g for a medium.

We were quickly converted when we reviewed the Protone last year, and we described it as 'a highly-adjustable, secure and well-ventilated helmet with a number of carefully considered features for riders in search of a lid which offers a claimed aero advantage without compromising on comfort'. We said ‘claimed aero advantage’ because Kask don’t put a number on the Protone’s aero efficiency – nor do we have a wind tunnel to test it ourselves – but you can take come comfort in Team Sky’s involvement.