Bug Tough. Family Friendly Go Beyond DEET! Child Safe All Natural Protection Swiss Formula Contains Plant Oils, Plant Extracts & Plant Derivatives 20 Herbal Wipes Bite Blocker s proven effective formula will protect you and your family from bites for up to 3 hours against mosquitoes and black flies. This organic formula was tested under rigorous field trials at the University of Guelph and was 90% effective after 3 hours. It is safe to use on the entire family from infants to the elderly. For maximum protection, re-apply every 2 hours.