This hydration pack is almost perfect. It has good space and hydration bladder. The velcro straps keeps them from slipping more open as happens to me with other packs. However, I have a fairly wide chest, 44" jacket, and the velcro chest strap has to be set on it's widest setting and still barely fits. It has come open when running. This is not even a concern with other hydration packs. Just 1" wider adjustment would have been great.