I purchased this for a repair job where I needed to fix/repair the outer sleeve/plastic covering of my generator wire running to my panel box. The current covering was cracked and had some wear on it so i decided to put a 30 ft. piece of heat shrink over it to make sure in have no exposed wires to hurt/kill anyone or my dogs. now pulling 6aug of 4 strand ridged wire through heat shrink. I have a couple of things, tips, and tricks I do to make it go easier. 1st, I identify the length needed and short it about a foot or so. Then I take a rod (as long as it is not sharp) tie and tape some string to the end of the rod, and thread the rod and attached string through the heat shrink, until your rod comes out the other side, and the attached string is now all of the way through. Tip #2 when you are trying to thread the rod and string through the Heat Shrink. You may find it easier to bunch up the heat shrink on your rod (making it look like a scrunchie), allowing you to grab the tip of the rod in the heat shrinkxxxxxxxxxxxxxx sliding the back Part of the heat shrink down the string. Repeating this process of bunching the heat shrink up on the rod and sliding the heat shrink down the string, until your rod appear out the other side. Trick #3, If you put some grease, baby oil, Dish soap(like Dawn), or anything that will allow the wire to slide frictionless through the heat shrink.Trick #4, once I am ready to pull the wire through the heat shrink. I cut the string from the rod and tie it to something that is steady enough not to brake or, fall off, or cause your string to be damaged forcing you to do steps 1,2 and 3 again. I like to use the refrigerator handle in my garage (just something sturdy), that will be ok to slide your heat shrink over your string and attached power cable.With your string attached to your sturdy object and the other end now attached to your string. You will start to move the heat shrink in the direction of where your power cable is attached to the string. As you slide your heat shrink down the string and over your power wire(s), (this is where you soap or oil will assist in the sliding).#5 you do not want to over pull the shrink, making your wire is still hanging out of both sides other wise you will have to try and get it back through, cut the excess off, or get your finger's in the shrink to be able to pull the wire back. If you over shoot your length it can be pain full to try to rectify the issue. so close pay attention. Once you get your heat shrink where you wanted it you can take a torch, heat gun, hair dryer, or even a lighter to heat and force it to shrink the smallest size or securely/tightly around the wires. leave room on the end to put what ever connectors you require to make the cable useful.Last Tip. after you have heated and shrunk the heat shrink identify how much length you need to cover and over lap the ends and fish the wire through the end cap not to shrink them until you have re/attached you end pieces for the power plug once that is on as you require then last step is to shrink the end pieces and over lap the longer piece you shrunk earlier.