Waterproof shrink solder connectors?

Ok so these are connectors I ended up buying on amazon. 4E1A073E-C4D4-436F-9551-DB30AF356967.jpeg

Here’s how they look on the wire before being shrunk
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And here’s after it’s shrunk with the low (750*) setting on a heat gun. As you can see, the solder melted very nicely. 78683F15-4FEA-435D-B9FB-E60D8CE547E1.jpeg This was a test piece of wire so I grabbed ahold of bothe ends and pulled as hard as I could and the splice never budged. I’ve tried soldering before and it was a major fail. These connectors make splicing wires SUPER easy!! A++ from me!!