OSIS SESSION hairspray 500 ml OSIS SESSION hairspray 500 ml is a professional styling product designed to provide long-lasting hold and maximum flexibility. It is formulated with a special blend of polymers and resins that lock in style and provide a flexible, yet strong hold. The aerosol spray is designed to be easy to use and leave hair with a natural, healthy shine. OSIS SESSION hairspray 500 ml is great for creating updos and special occasion styles that last all night. It is also great for keeping short styles in place and controlling flyaways.