The Salomon Advanced Skin 5 Set Pack is a trail running vest for keeping small essentials close. Breathable fabrics that run close against the body prevent chafing. Front chest pockets holster the 2 included soft flasks, while the back stretch mesh pocket will happily carry some energy gels. The elastic chest straps prevent unwanted movement. Utilize the internal pocket if you wish, or don't. Although not included, the pack is compatible with a 1.5L bladder if you are looking to do longer miles.