This 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.50% DEET and 0.1% Pyrethrin - high level protectionDual-action formula offers up to 10 hours protectionDurable bottlesSuitable for children over 6 yearsThe repellent will last 24 months from when it is first opened DEET is proven to be the best repellent against mosquitoes available. This comes in different strengths and the higher the percentage, the more effective it is and the longer it lasts. The most popular strength is 50% DEET but we recommend you get one with a bite inhibitor (PLUS+)