Ultrasonic pest control repeller

the Device emission multi-frequency waves to prevent mosquitoes from developing immunity from the mosquito repeller, the working mode as follow:
Mode 1: the device emit ultrasonic wave imitate the sound of male mosquitoes to drive away the female mosquito who bites people.
Mode 2: the device imitate wing beat sound of dragonfly who is the natural enemy of mosquitoes to scare the mosquitoes away.
Mode 3: Combining the above two functions.
1. Outdoor use - suit for travel, fishing, camping, hiking and so on.
2. Break away from harmful chemicals and toxic solvents, safe for human and pets.
3. Power supply by 2pcs 1.5V AAA battery (not included).