What is difference between par 38 and par 40 outdoor security light?

The main difference between PAR 38 and PAR 40 outdoor security lights lies in their size and light output. PAR 38 bulbs are typically 4.75 inches in diameter and are commonly used for residential lighting, providing sufficient illumination for outdoor areas. In contrast, PAR 40 bulbs are larger, measuring about 5 inches in diameter, and generally produce a brighter and more focused beam, making them suitable for larger or more demanding outdoor security applications. This size difference also affects their wattage and lumens output, with PAR 40 often offering higher performance.