Reddit reviews Tool Band-It Magnetic Arm Band - Black
We found 3 Reddit comments about Tool Band-It Magnetic Arm Band - Black. Here are the top ones, ranked by their Reddit score.

Light-weight, flexible and ergonomic
The problem with arm bands, is that they are harder to access, because unlike a toolbelt, raising your arm above your head inverts the pocket, so you either need to add an extra step of sealing the pocket/unsealing it everytime you want something, or the risk of having stuff fall into your eye when reaching above your head, not to mention these things are small sharp tools. Elastics are not that forgiving, especially as an exterior layer when exposed to the cold.
That's why billy mays went with magnets
https://www.amazon.ca/Tool-Band-Adjustable-Magnetic-077-1025/dp/B000ICT8OY
Or you could spend $4 and get this http://www.amazon.com/Tool-Band-It-Adjustable-Magnetic-077-1025/dp/B000ICT8OY/ref=sr_1_2?ie=UTF8&qid=1348758874&sr=8-2&keywords=magnetic+wrist+band
Simpsons did it.
https://www.amazon.com/Tool-Band-It-Magnetic-Arm-Band/product-reviews/B000ICT8OY
As I tradesmen who climes a lot o ladders and scaffolds would never be able to use the product you're describing.