A class 3 nebula in the Delta Quadrant
"Next time you run across a Class 3 nebula, think of me."
A Class 3 nebula was a type of nebula.
In 2375, Derran Tal detected a Class 3 nebula from the Varro generational ship. Harry Kim secretly took her there in person, using one of USS Voyager's Class 2 shuttles. They found that there was a subspace vacuole near the center of the nebula, acting as a gravitational anchor for the surrounding gas. (VOY: "The Disease")