The Flanders Warm LS Base Layer is a thicker version of the standard issue Flanders base layer. And thus, adds more thermal value which keeps you warmer in colder temps. The base has a distinctive grey color to up the heat absorption. It also helps differentiate this garment from the other base layers in your drawer.
The entire body of the Flanders Warm LS is constructed from SottoZero Fleece multi-denier poly fabric that has 3D structure and a rib-knit profile. Let's break that down. Denier is a unit of linear mass of the density of fibers, so multi-denier simply means several different densities of fibers. This multiple density construction creates a 3D structure that elevates the fabric off of the skin which greatly improves wicking and moisture management. Rib-knit is the corduroy looking profile of the material that promotes air flow. Castelli combines multi-denier 3D fabric with a rib-knit profile for complete success with wicking and moisture management.
Other details include a 4-needle flat-lock stitching that lies perfectly flat and will not bind. A crew neck profile for added comfort and a flat finish bottom to prevent bunching when tucked into your bottoms. Any rider who enjoys cycling in 3 season conditions should have one of these in their arsenal.