Coaxial LED mini lights have a water tight seal when connecting two strands together. Coaxial strands are great for wetter climate's and areas located closer to the ocean. You will need a coaxial power adaptor when using these types of strands.
Depending on the amount of watts each strand has, most LED mini lights can connect up to 45 strands end to end. You will want to reference the tag located on the strand for wattage information for the Mini light strands you purchased.