Scuba Flag???

[ANewHope]

Time for another newbee question. I am just starting to go out diving more, now that I have my own gear. I was remembering somthing in my PADI class about divers needing to have flags. So, I poked around with my good friend Google and discovered what the MN regulations are for SCUBA divers.

REGS:

Anyway, what I want to find is a flag, as described above, that floats on the surface, but is attached to me with some sort of a spring-loaded real that will take up the slack as i go deeper/more shallow. In the research I've been doing I cant seem to find aything like this. Ive seen the little plastic thingys that look like a kite string holder, however they look useless.

Any Ideas? I'd love to hear them.