This "canned air" product works fine. The actuation mechanism seems decent and the cans seem as full as any other I've used. All good; I would buy again and I recommend it...
with one exception
The packaging from Amazon was terrible. The cans were individually packed in plastic air-filled wrappers, which was OK, but the whole set was just put in a large box, and when they arrived, one of the cans was useless because the cap / nozzle / trigger assembly had been struck hard, I guess, and broke off the top of the can, taking the can's nozzle with it. So one can DOA because of terrible packaging.
Most of the time I'm pretty satisfied with Amazon's packaging, but this was a notable exception.