I bought these on eBay recently. I haven't tried them. I'd bought these eBay after waiting 3 weeks for ones I'd bought directly from manufacturer to arrive. I needed them urgently before going on holiday with an injury so I could do my strength training while away. Selling for 50% of what I bought them for because the banding isn't quite the same as that of the ones direct from AirBands. You can see the difference if you look online. These turn on (see photo) as expected but I haven't done anything else to test them. Price adjusted to reflect the risk. AirBands direct are £350+.
eBay