The Nike Running Holiday 2011 “Dark” enjoys its official unveiling here. A trifecta of running-centric releases also encompasses the “Rain” and “Cold.” The “Dark” collection is based on the notion that runners receive much less daylight in the wintertime, and need specially engineered products to cope with the substantial loss of light. Most pieces are created to help runners stand out in the dark, like the Vapor Flash Jacket, with 400 candle power reflectivity, and the Swift Tight, which has a reflective strip on the zippered back pocket. The Nike Free Run+ 2 Shield rounds out the collection, adding reflective material on the traditional lower lattice design to maximize visibility in low light. All of the pieces use the principle of retro reflection – most of the light goes directly back in the direction it came from instead of in all directions, making you much more visible to oncoming traffic.