Power Ring

From HallsWiki

A Green Lantern power ring is capable of drawing on the bearer's willpower to create elaborate green constructs out of a form of "hard" light. It is regarded as being one of the most powerful weapons in the universe, and a capable wielder of a power ring is a match for even Superman. Traditionally there is a weakness against the color yellow, though some are insusceptible to this, and a mastery of fear allows one to overcome it.

McCrea wields a power ring of his own construction, and for many years Slovman wore one that lacked the yellow flaw.