By far the most popular types of lights for garden decking are LED deck lights. They use a solid-state technology that is resilient to vibration and shock, they last for eons - conceivably longer than those of us that install them - and they’re extremely low powered. They can also be made with very small housings, as they don’t emit significant heat, nor require pampering.
Deck lights typically are low voltage, come in kits complete with LED drivers or transformers, and boast varying Ingress Protection ratings that will guarantee anything from straight protection against the weather to resistance in the face of high-pressure hoses. For thorough protection against both dust and jets of water, an IP65 rating is ideal, although lesser ratings are perfectly suitable for the majority of regular applications and environments.
The purpose of deck lights is really two-fold: to define the decking area for safety reasons, and to provide a pleasant, understated light that glows just enough to serve its function. Decking lights are a great way to make your garden deck a more relaxing place.