These bulbs or lamps come in a variety of "beam angles" or "beam spreads" to meet these highlighting needs; the smaller the beam angle, the smaller an area the light will cover. Of course this will also be affected by the distance of the bulb from the area or object being focused on.
PAR bulbs are also commonly used in outdoor fixtures as either spotlights (narrower beam angle) or floodlights (wider beam angle). Some of them come sealed and "wet location rated" for this purpose, and you can look for this rating in their specifications when purchasing PAR bulbs if you'll be using them outdoors. You can also choose "damp location rated" bulbs if they will largely be protected from the elements and will only be exposed to humidity, fog, or the occasional wind-whipped snowflake.
When you choose PAR LEDs, you not only get the traditional benefits of LED lighting -- like extremely long life ratings and low energy usage for big savings -- but you also get a technology that emits almost no heat with the light. This doesn't make much difference outdoors (unless you need the bulbs melting snow), but when used as highlighting bulbs, you can help to protect art and furniture by minimizing the heat directed at them. Unlike fluorescent lighting, LED also emits little to no UV, offering another level of protection.
We'll discuss three primary sizes for PAR bulbs and, as with other types of bulbs, these sizes determine what we call them. These sizes and their common uses are described below.
PAR30 lamps are unique in that they come with both short neck and long neck options. This gives you flexibility in terms of how you want the lamp sitting in a recessed can (hidden further inside or extending a bit). Traditionally, though, long neck PAR30s are used in recessed cans while short neck PAR30s are used in track lighting.
PAR38 LEDs also come in the highest wattage options, making them useful anywhere you need the light reaching further -- from two-story ceilings for instance, or in outdoor floodlight fixtures.