Or “What is a downstage monitor?” or “How can I make sure my presenter sees their slides?”
Did you ever take a public speaking class? One of the points they always stress is the importance of eye contact and engaging the audience. When your presenter is speaking often the computer isn’t visible, which means they have to constantly look backwards, which can throw off the vibe.
A confidence monitor is an additional screen facing the presenter which mirrors the content that the audience sees. A confidence monitor can be very small and placed on or near the lectern, or more often it’s a large flat panel display set on a stand on the floor. Besides helping your presenters, having a confidence monitor also gives your event a more polished, professional look.