Which device supports stage lighting at varying heights?

The Light Tree is specifically designed to support stage lighting fixtures at varying heights, making it the correct choice for this question. A Light Tree typically consists of a vertical pole or structure where multiple lighting instruments can be mounted, allowing for flexible arrangement and optimal positioning to achieve desired lighting effects on stage. This versatility is crucial for theatrical performances and live events, where precise lighting is essential to create the right atmosphere and highlight specific areas of the stage.

In contrast, an Audio Mixer is used for managing audio inputs and outputs, a Riser is typically used to elevate performers or set pieces rather than lighting, and a Seamless Switcher is primarily focused on managing video sources. These other devices, while integral to event production, do not specifically support the height adjustments for stage lighting that a Light Tree does.