Total personal protection from pesky mosquitos wherever you roam: your yard, the park or near water (just clip to your belt!). Chemical-free repeller uses ultrasonic (sound) waves to drive bugs away (up to 30 sq. ft. of protection!). On/off switch. Indoor and outdoor safe; pet safe. Each repeller uses 1 AA battery (not included). 3/4" diam. x 3" l.