There's no denying that high-quality down is the champion at providing warmth in dry weather. But, it also has several downsides; such as being unnecessarily heavy and not waterproof. This is where PrimaLoft comes in; currently the leading brand in synthetic insulation. PrimaLoft insulation was designed to mimic all the great properties of down, but to also go one step further and provide superb protection even in wet weather.