These connectors are good for general dry use but definitely not as good as any other connectors I have used and advertised for marine use. These connectors have heat shrink caps, but the plastic is hard and takes much longer for the heat gun to shrink, has little adhesive on the inside to create a watertight seal, and is completely solid after cooling compared to other marine connectors, I used lots of heat activated glue to keep water out, shrink/melt quickly at lower temperatures, and remain soft and pliable when cool. I also cut several connectors and none of them contained copper inside. are functional basic aluminum connectors, but they do not live up to the advertised marine quality.