A helmet construction for protecting a user's head, and the brain within the cranium from impact forces, includes a shell contoured to the shape of the user's head, with cushioning along at least part of the shell interior and a chinstrap. The shell consists of three (or more) discrete panels that are physically and firmly coupled together providing rigid protection under most circumstances, but upon impact the panels move relative to one another, but not relative to the user's head, thereby permitting impact forces to be dissipated and/or redirected away from the cranium and brain within. Upon impact to the helmet, there are sequential stages of movement of the panels relative to each other, these movements initially being recoverable, but with sufficient vector forces the helmet undergoes structural changes in a pre-determined fashion, so that the recoverable and permanent movements cumulatively provide a protective 'crumple zone' or 'shear zone'. The first two stages of protection arise from the design of the fasteners that have the ability to invaginate and collapse within themselves, and their design having a 45 degree angle, which will allow movement of a region of connected panels to translate along the fastener shaft. Both of these movements will be recoverable and provide a 'functional crumple zone'. The final stage of protection arises from the braking function of the pins, as they are forced from one aperture through to the next, the direction and extent of which is determined by the impact force and direction. This final level of panel movement and protection is not recoverable and thus provides a 'structural crumple zone'. Finally the fastener size and thickness, together with the thickness of webbing and distance between apertures, functions to provide varying degrees of resistance to impact forces, thus making the helmet design suitable for activities with different levels of impact speed and risk potential.