Our Insect Repellent - Expedition 50 range contains a dual action formula which combines pyrethrin with DEET to provide a high level of protection against biting insects in all environments. The pyrethrin acts as a bite inhibitor, discouraging actual biting insects including mosquitoes. Each application of Expedition 50 will last for up to 10 hours. Re-application may be required in areas with high temperature and humidity.