Step stair lights can use various types of bulbs, depending on the specific light fixture and its requirements. Here are some common types of bulbs used in step stair lights:

1. LED bulbs: LED bulbs are becoming increasingly popular for step stair lights due to their energy efficiency and long lifespan. They are also available in a variety of color temperatures and can provide a bright, high-quality light.

2. Halogen bulbs: Halogen bulbs are another common type of bulb used in step stair lights. They are typically brighter than LED bulbs but use more energy and have a shorter lifespan.

3. Incandescent bulbs: Incandescent bulbs are the traditional type of bulb and are less commonly used in step stair lights due to their inefficiency and short lifespan.

When choosing a bulb for a step stair light, it's important to consider factors such as brightness, color temperature, energy efficiency, and lifespan. LED bulbs are generally considered the best choice for step stair lights due to their low energy consumption, long lifespan, and high-quality illumination.