Its lo-tech, it always works and it works well.
On one occasion, at Roca Soucia in Cocos Island, I came up about half a mile from my pick-up boat and deployed it. Divers in another boat six miles away didnt know what it was, but they could see it. Thats what I call effective.
I have used it in earnest many times over the years - Im that sort of diver. Im always getting separated from the other divers at remote locations.
My big yellow flag extends on three lengths of plastic tubing held together by a length of elastic cord that runs through it. It has a lanyard. I stow it on my tank under a couple of bungee bands, the type under and alongside which I can stow my long-hose octopus. I bought my flag for around £17, but you could easily make one yourself for less.
It was inevitable that someone would come up with a more sophisticated manufactured version. The HELP (Handheld Emergency Location Pinpointer) flag is intended to be equally effective.
It has a 70% glass-fibre composite pole that telescopes out to about 1.5m (the same as my lo-tech flag) from a tube that easily fits into a BC pocket. There is provision to fit a lanyard, which I would say is essential.
However, despite whatever good intentions the manufacturer may have had, I discovered a couple of problems.
After the HELP had been in my BC for a week, the end cap that reveals the pole-end had become almost impossible to remove.
And once it was extended, I found that the flag was far too small. It was almost invisible once I was more than 100m from the boat, and visibility is what its all about.
Not only that, but after use I had a lot of trouble wrapping the flag tightly enough to go back whence it came. All these drawbacks, and it costs £30, too.

Comparable flags to consider:
Bowstone Pop-Up Flag, £18

SPECS
PRICE £30
LENGTH 20cm, extends to 150cm
WEIGHT 150g
contact www.thediveflag.com
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