Each ThermaCELL Mosquito Repellent Appliance or Lantern creates a 15 x 15 foot "Bug free zone". They have been proven in worldwide testing by the US army to repel up to 98% of mosquitoes, black flies, no-see-ums and other flying insects. Small and easily portable they are great in the backyard, camping, picnicing, hunting, fishing - anywhere in the great outdoors.