Most just purchase.. I have actually used it. I have two one from my whitewater days which is 100 feet of floating line and the other for Canadian requirements ( 50 feet)
I started looking at heaving lines/rescue bags, and was unaware of the vast variances available.
Length of line
Diameter of line
Lb. test of line
material of bag
throwing handle placement
Do any of you have a preference for someone with no experience with these systems?