bicycle handlebar tool bag for extreme conditions

bicycle handlebar tool bag can expand up to 2 litres but still fits fairly neatly under the saddle with a nice aero wedge shape. lightweight bicycle bags fits my spare tubes, levers, mini pump (for pumping tyres up - not insulin!!), blood glucose meter, insulin pen, hypo gels, phone, keys, wallet - i.e. it can fit a lot. I use my jersey pockets to put food in - banana, malt loaf, flapjack etc.