The advantages of lighted extension cords are twofold: Lighted ends indicate that there is power running throught the cord so you know it's plugged in; and secondly, the cord has more visibility in the dark, around a corner, or in dirty areas. Unique to Century's premium cord line is the patented CGM (Continuous Ground Monitoring) connector. This connector has a green light which indicates that there is ground continuity in the circuit. Simply put, the cord is grounded safely when the green light is on.