As someone who has a degree in acoustics and worked in Acoustic consultancy for 7 years, I can say with some certainty that this will not work as advertised. Quite simply, you can't change the laws of physics.
If you want to effectively cut out noise from your environment either build some thick walls around yourself or use 20p foam earplugs in combination with ear defenders (you can pick 40dB 3M PELTORs for £18 on Amazon). They will be significantly better than this snake oil device and will save you alot of money!
If you want to effectively cut out noise from your environment either build some thick walls around yourself or use 20p foam earplugs in combination with ear defenders (you can pick 40dB 3M PELTORs for £18 on Amazon). They will be significantly better than this snake oil device and will save you alot of money!