What agency

[captain]

I wonder what agency it was certified by.

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[BDSC]

What would it be used for? Weight to get down I would assume in older diving set-up?

[scwdive]

I had to tread water with one of these over my head to earn my water safety instructor cert. about 20 years ago. Also fairly common was to recover it from the deep end of the pool and swim laps with it held above the water.... We dove down to recover it....

Best

[UnderwaterMedic]

Not sure, but holding one over my head doesn't sound too fun. I can just imagine dropping it on my head...

[diversteve]

It's rubber so it doesn't scuff the pool sides/bottom. Seems a little overpriced though new ones are $20+: Amazon.com: Dive Brick: Everything Else (http://www.amazon.com/Aqua-Gear-Direct-Dive-Brick/dp/B001QTCLZQ)