Cold sweat that remains on the skin during high-speed descents in late-fall and winter can immediately take the impetus out of pursuing further base miles, if not leave you shivering for some time. Castelli's Prosecco Tech Long-Sleeve Base Layer is a discreet and useful tool at managing performance goals during winter riding. As sweat accumulates during hard pedaling, the Prosecco's hydrophilic treatment superb wicking transports sweat from the skin, while the Primaloft fabrics provide welcomed insulation.Castelli takes it a step further, and strategically maps the Primaloft to have less density in areas covered by bib straps and short's backing to minimize the effects of over-insulation. It's easy to have a stuffy ride feeling when over-insulated, so we're glad to see this thoughtfulness from Castelli. And the wide-set collar remains less visible under jersey tops for a clean and professional image.