Well DEET has been around for a very long time, has proved its worth as a super-effective repellent and has never been shown to cause harm, even to children. It will attack things like plastic shopping bags and watch straps and will stain your skin in consequence, but you allow that once and avoid it from then on. Research has shown (yes, weasel words red alert...) that roll-ons and wrist bands are completely useless. Any repellent must cover every inch of bare flesh.