A support structure for supporting the user of a mobility device or the like, the support structure comprising a fluid flow channel, the fluid flow channel comprising a fluid inlet and a fluid outlet, wherein at least part of the fluid flow channel is tapered, the at least part tapered fluid flow channel comprising a first end and a second end, the first end of the at least part tapered fluid flow channel being located proximal to the fluid inlet and the second end of the at least part tapered fluid flow channel being located distal to the fluid inlet,and wherein the width of the second end of the at least part tapered fluid flow channel is greater than the width of the first end of the at least part tapered fluid flow channel.
