These grease filled connectors are designed for outdoor use. I used them to connect 18 gauge wire to the sprinkler manifold and they worked fine. I bought a few more than I really needed, but that was because the price of this bulk pack was so good that I decided it was better to have spares than to pay a higher price for less. Also, they can only be used once, and installing a sprinkler system can be a bit of a trial and error process, so having a replacement or two can save you a lot of time…