From Quake Wiki
Description: Template:lowercase-underscores trigger_multiple, as opposed to trigger_once is a simple trigger that refreshes consistently, that can target another entity, killtarget or centerprint a message via its message field. It is applied to a brush, typically using the trigger texture which is rendered as transparent, and when the player collides with it, it performs all functions in its fields, such as stating which difficulty the hallway you are in represents in start.
It is typically used in cases of important information you want to be sure the player is aware of, and not plot points or narration. Recommend usage involves a brush no thicker than a player's bounding box, so they don't trip the event multiple times while walking on through (unless this is explicitly what you do want). Another use is switch operated doors, if a door closes by itself, but you want the player to open it again remotely, such as standing on a certain texture of the floor.
|style "#"||32 works|
|target||Trigger name of targe.|
|sounds||Sound made when triggered. See Table below.|
|wait||Delay until it retriggers, some classes only (optional)|
|delay||Delay before action is triggered.|
Sounds - the different sounds triggers can make when activated.
|Blank means no sound.|
|4||Set message to text string, can be used to show messages.|