If you are joining multiple strips of tape lighting, you may need more wire than is included in the kits.
White LED tape lighting uses two-conductor wire. If you are connecting multiple individual white LED lights, for example, mini lights or downlights, two-conductor wire is needed.
For color-controlled lighting, two-conductor wire can be used only to connect the power supply to the color controller. (All other wiring connections involving color-controlled lighting require four-conductor wire.)
This indoor/in-wall rated, stranded wire is supplied as a 26.2' (8m) roll. The 22 gauge is suitable for short wire runs. The heavier 18 gauge wire is a good choice to reduce voltage drop when using longer runs of wire and when using multiple individual LED lights.
Note that outdoor installations or those in wet locations, like shower enclosures, require the use of outdoor-grade connectors and wire, in addition to outdoor-grade lighting.