We were using Shark Shield Freedom 7 units, which is earlier model i think, in diving operations for 500 diving hours. There are young hammer heads and bull sharks around fishing harbors and fish factories here. Local divers reported seen those every now and then. Our divers were never bothered by sharks. We saw sharks from the boat so i know that there were sharks around.
Yes, sharks do make me feel uncomfortable when they are around. The fact is that when one has a job to do underwater, a job that requires a full concentration, it is simply not possible if those killing machines are there. I am not sure if these give 100% protection but U.S. navy is using them and there are independent tests done too and according to my experience they work.
We were using those with full wet suits and also with dry suits and Interspiro Mk2 apparatus, not just a full face mask but the whole apparatus.
I do not care what those romantic shark lovers say, sharks are wild predators who act according their instincts.
My lads use one each and they dived every day in some of the most shark (and crocodile) infested waters on this planet (pearl farming).
The shields work a treat!
That said there were 'problems' - where they dived a steel hulled shipwreck... the trailing part when it contacts the steel I beams of the hull transmits to pulse to you if your hanging onto / touching any other steel part of the hull.
Also if either manages to brush / touch the others trailing part a jolt or 3 should be expected.
Both lads still saw sharks most days -but weren't "bothered" by them while wearing the shields.
Pretty much we didn't spear fish while diving coz in those waters its just asking to get bit.
We seemed to have our share of big sharks follow the calving whales on their migration past us and also some reasonable sized snappin handbags.
No bites while wearing the shark shields & the 2 lads swum the pearl lines every day.
If you see me swimming with sharks, you may rest assured that someone threw me overboard. I do, however, admire those brave enough to face the odds to bring History to the surface.
Marvin