Like your favorite down puffy, the Elemento Lite Jacket provides protection from the cold at an impressively low weight. It’s inspired by technology from high-end mountaineering jackets where the perfect balance of warmth, breathability, and low weight is critical. The intended use is high-intensity cycling in cold temperatures, where warmth is important but breathability is absolutely vital. It’s not a race cut jacket like the Alpha series. Instead, the Elemento Lite fits slightly looser due to the fabrics it’s made of. It’s certainly more breathable though, with comparable levels of insulation. The Elemento’s construction resembles a mountaineering jacket, being composed of a layer of insulation sandwiched between two woven nylon layers, with the outer layer using a water-resistant treatment to shed light rain or snow. Unlike most alpine jackets, this one isn’t totally windproof. Instead, Castelli engineered a small degree of permeability. The little bit of air that gets into the jacket picks up moisture and evaporates it more efficiently than any membrane fabric, keeping you dry when tough intervals or hard climbs cause unavoidable perspiration. The insulation layer is polypropylene, which is a synthetic down material that allows full breathability without any water absorption, and is also incredibly light. These fabrics have limited stretch, which is why Castelli opted for a semi-fitted cut rather than a full on race fit. In order to not sacrifice mobility, there are plisse stretch panels on the sides, elbows, and wrists that preserve 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.