Castelli believes so much in the power of the fabric it uses to craft the Core Mesh 3 Sleeveless Baselayer that it deviated from its usual performance-related fabric monikers and named it Magic Mesh. Before you get skeptical about the fabric's otherworldly name, consider that the brand omitted all traces of less breathable Lycra when constructing the mesh, using only the most breathable polyester fibers to ensure maximum moisture management. By putting this featherweight layer under your summer jersey, you'll actually help speed up the rate at which moisture is pulled away from your skin to evaporate, helping you stay cooler and drier as you push through hot, humid air.