Lifesystems Expedition 50 Insect Repellent is formulated to provide long lasting protection, even in difficult conditions. Each application of Expedition 50 lasts for up to 8 hours. Re-application may be required in areas with high temperature & humidity. Features Formulation: 50% DEET Effective for: Up to 8 hours Repels: Mosquitoes, midges, horseflies, sandflies, gnats, fleas, ticks & other biting insects. Glossary DEETDiethyl-meta-toluamide, abbreviated DEET, is a slightly yellow oil & is the most common active ingredient in insect repellents. It is intended to be applied to the skin or to clothing, & is primarily used to repel insects, in particular mosquitoes. It is used in concentrations up to 100%, with DEET 100 offering the most hours of protection.