Is the ultrasonic mosquito repellent really effective?

According to my personal experience, ultrasonic mosquito repellent is fake and ineffective, because only male mosquitoes are sensitive to sound, while male mosquitoes do not suck blood. It's this tattoo that sucks blood. They're not that sensitive to sound.

The working principle of ultrasonic mosquito repellent is to imitate the vibration frequency of dragonfly or male mosquito wings to disperse female mosquitoes. In general, the vibration frequency of the wings of listening or male mosquitoes is 250 to 600Hz, but the ultrasonic mosquito repellent can't achieve this effect at all, so it can't achieve the purpose of mosquito repellent. In fact, we can use the simplest method to drive away mosquitoes, such as mosquito nets, toilet water and so on.