Active Guard Mattress Liner King Size. They are treated with Permethrin and will continue to kill bed bugs and dust mites for two years. ActiveGuard Mattress Liners are the only mattress liners that actively kills bed bugs within 72 hours. These liners not only kill the current bug infestations but will protect against new infestations. ActiveGuard Mattress Liners have been implemented in major hotel chains internationally and nationally. ActiveGuard Liners were initially developed as a tool against dust mites that produce asthma-associated allergens by a team of medical entomologists in London. These durable mattress liners were developed as a natural extension of the globally accepted use of malaria nets. Permethrin-impregnated bed nets have been used for decades to provide mosquito protection because of the repellent nature of permethrin against mosquitoes. EPA issued a new label for ActiveGuard Liners in 2012, removing use restrictions; it is available for people of all ages, even small children.