The WeighMyGear Shop Supplied by

Built for hot summer days in the mountains, Castelli's Climber's 4. 0 Jersey keeps us cool without sacrificing speed with its lightweight fabrics and rapid cooling properties. This high-alpine-focused jersey features the same aerodynamic CFD-based seam construction as the Aero Race 7 jersey but with 3D mesh fabrics that keep us cool and comfortable as we ride through the summer heat.