Whether you are a fan of bike helmets or not, the Hedkayse helmet will make an interesting talking point. Not only is it foldable – down to 10cm – but the helmet is designed to withstand several impacts, instead of being binned after a single impact. It is made from a polymer that has been shown in tests to survive several impacts undamaged, and has the European safety certification to back it up. That means that not only is it tough, but one helmet can also be adjusted to fit head sizes from 49cm to 62 cm. So it is flexible all round for users.