Replaces 4 incandescent bulbs with these LEDs in about 10 minutes. I love being able to adjust the fit to a 5" or 6" glass with a simple screw. The springs and hardware were very good and firm...no sagging. The brightness was great. The manufacturer's packaging could be better. All 4 headlights were stacked in a box with no separation between blocks resulting in minor wear to the headlight bezels but not visible from ground level once installed. The Revain packaging was good. Would buy again.