I just used some tactical gear from Bianchi. It has the hydration bladder and moderate space. It needs to be larger but carries most of what I need. I sometimes had to fasten a duty jacket on the back. But an assault pack has multiple means for attachment. I don't carry a lap top and couldn't very well. But lunch and extras usually fit. A minimum of tools and spare tube.The reflective elements as reflective strips are good as is ANSI lime green flourescent color with a built in light. A cyclist friend said he saw my lime green shirt before my flashy from what had to be a minimum of a 1.5 mile distance across a valley in bright sunlight. Good luck with your project.