County Comm now offers 'The Drop-Line RLD System'. The Delrin Drop-Line roll is a definite improvement over the PVC pipe and recycled plastic spools that I used with my projects a few months ago.
Some folks like to have readily accessible cord that's not knotted, kinked, or tangled up when they need to use it. Having one or two of these attached to your gear is just being prepared.
I wound up some cord on a couple of them, and was able to get 50 ft of 550 paracord on one, and 100 ft of 3/32" tether cord on another.
The Delrin roll has just enough give in it so that it can be removed/replaced, but it's not going to come off the carabiner until you want it to. The load rated Omega locking carabiner can also be put to use when the cord is emptied off the wheel .
*Note this is just a device meant for storage and dispensing of cord, not a life saving/support piece of equipment, so use responsibly.