This arrived yesterday. Paid MYR 10.90 for it. Didn’t expect it to really work. Tested it with my phone’s ultrasound detector. It was going haywire on the 20.9kHz range.
Tested it on my neighbour’s dogs tonight. They were surprised by it and learnt to stay 10 feet away from me and kept quiet. They were annoyed by it and learnt not to bark. Because every time they bark, I will point at them and turn it on.