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.

Abstract: A drum head tuning apparatus for tuning a drum or similar percussion instrument is disclosed. The invention includes a distensible bladder having an annular shape that is disposed between the drum hoop and the rigid outer circumferential lip of the drum head. When the head is mounted to the drum shell and the hoop is locked down by tensioning members to the lugs on the outside of the shell, air is pumped into the bladder to increased the bladder's volume. The expanding bladder displaces the circumferential lip and consequently pulls the drum head tighter over the opening in the shell to raise the pitch of the drum. Conversely, releasing air pressure from the bladder allows the stretched drum head to spring back thereby releasing tension and lowering the pitch of the drum.