Review on Insulated Wire Electrical Connectors Assortment by Andrew Griggs

They work if you are in a place where you can use a heat gun. However, if you don't and have to use a lighter or flashlight, you'll melt and completely destroy the heat shrink tubing long before the solder begins to melt. Even with a heat gun, I feel like I'm heating it up three times longer than I need to. Just to see how quickly I could melt one of them with a small pocket torch like you get from a smoker, I turned it on full blast and aimed the flame directly at the solder. It took a good 10 seconds to melt and the heat shrink melted and caught fire in about 3-4 seconds. Anyone who has ever decided to use ultra-high temperature solder for this application is not very smart.