Inspired by technology found in the world of mountaineering, Castelli created the Elemento Lite Jacket for protection from the cold at an exceptionally low weight. It's designed for high-intensity cycling in brisk temperatures, when warmth is important but breathability is paramount. It's not a race cut jacket like the Alpha series. Instead, the Elemento Lite fits slightly looser due to the fabrics used. It's certainly more breathable though, with comparable insulation. The Elemento is constructed much like a mountaineering jacket, using a layer of insulation sandwiched between two layers of woven nylon, with the outer layer employing a water-repellent finish to shed light precipitation. Unlike most mountain jackets, this one isn't completely windproof. Instead, Castelli engineered a small amount of permeability. This little bit of air that gets into the jacket helps pick up moisture and evaporate it more efficiently than any membrane fabric, keeping you dry when tough climbs or hard intervals cause inevitable perspiration. The insulation layer is polypropylene, which is a synthetic down material that allows fully breathability without any water absorption, and is also incredibly light. As alluded to above, these fabrics have limited stretch, which is why Castelli went with a semi-fitted cut rather than full on race fit. To ensure mobility, there are plisse stretch panels on the sides, elbows, and wrists that allow freedom of movement on the bike. Castelli finishes the jacket with an inner waist closure that lets you seal out drafts, or you can open it up for extra ventilation.