Hi. I have some questions about the Air Chek home radon testing kit.

http://www.radon.com/radon/radon_airchek.html

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First of all, the instructions say that I have to write my name and
address on the packet, using a waterproof pen.

What is a waterproof pen? Is any felt-tip pen a waterproof pen?

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Also, I'm supposed to use the packet's hook to hang the packet at my
normal breathing level.

Am I supposed to somehow hang the packet from my ceiling? What if my
ceiling doesn't have anything from which a packet can hang? Should I
tie one end of a piece of string to the packet's hook, and then tape
the other end of string to the ceiling?

Thanks for any information.