Abstract: A helmet (10) which has a plurality of substantially longitudinal members (20) arranged side-by-side, the longitudinal members (20) being in fluid communication with each other. It has a first inflated state in which the longitudinal members (20) are distributed to form a substantially concave shape, and a second compressed state in which the longitudinal members (20) lie flat and substantially coincident against each other. Each longitudinal member (20) is separated from neighbouring longitudinal members (20) by a tubular connecting member (30) in a lattice configuration. The helmet (10) may be made of HDPE or nylon.