K&S TECHNOLOGIES Heat-Shrink Solderless Wire Connector Kit/Refill — 12–10, 16–14, 22–18, 26–24 AWG, assorted colors
No soldering gun required; low-heat solder activates with a heat gun to create a watertight shrink seal. Packs come in a clear jar with barcode-labeled packs for easy counter or service use.