Baselayers & Undergarments

The Merino Seamless Long Sleeve Base Layer is the holy grail of base layers. As cozy as your favorite pair of wool slippers, yet it transfers moisture like water going through osmosis. It's the perfect recipe for a cool-weather layer courtesy of its Merino and synthetic fabrics. So, when you need to remain consistently warm on chilly days, look no further than this cool-weather staple. - Merino and synthetic yarns are blended to create a soft, insulating, and moisture-wicking layer, while also retaining a compressive feel. - Fabric Content: 40% Merino Wool, 40% Polyester, 20% Polypropilene

Light insulation, seamless comfort, and full-arm coverage in a long-sleeve base layer for colder conditions encountered in late fall and early spring. It's crucial that our upper body gets an added boost against the elements during those cold fall and early spring conditions. As a solution, we developed the Spring/Fall LS Skin Layer, which has taken the torch from our iconic Skinfoil base layers with a completely revamped design and all-new blend of fibers. To start, we've lowered the weight by about 8% and used a tubular knit technology that's free of irritating side seams. A cool-weather-tuned blend of carbon and polypropylene yarns are employed to pull moisture away from your skin and insulate your core, keeping you dry, insulated, and comfortable from the outset. The thicker Circular Seamless construction introduces a tubular knit that's free of side seams, creating an ultrasoft, comfortable feel against the body. The sleeves are sewn directly into the armhole to promote a full range of motion beneath additional layers.

Insulate yourself against the harshest winter rides with Castelli's Flanders Warm LS. Made to withstand your coldest days on the bike, the Flanders features SottoZero Fleece fabric for exceptional warmth. Flatlock stitching ensures a smooth feel against your skin, and mesh armpit inserts allow venting right where you need it. A flat hem tucks easily into tights so you avoid bunching, while the high collar keeps your neck warm and drafts at bay. PRODUCT FEATURES - SottoZero Fleece multi-denier 100% polyester fabric - Flat-lock stitching - Mesh armpit insert - Flat hem tucks away in tights - -4°-10°C / 25°-50°F - Weight:184g

A long-sleeved base layer tuned for the cold, demanding conditions of winter riding, featuring an insulating knit structure and seamless construction to keep you dry and insulated from the base up. Temperature regulation is the key performance indicator of any base layer, and this is especially true for a winter version. But winter poses a specific host of challenges not found in other climaCodes, namely in the form of added cold air and your additional layers. This is where our new Winter LS Skin Layer fills the gap, tuned with a thicker knit "weight," taller collar, and more stretch than our Spring/Fall version for boosted insulation and flexibility under your outer apparel. A winter-tuned blend of carbon and polypropylene yarns—plus elastane— are employed, which draws moisture away from your skin and insulates your core, keeping you dry, insulated, and comfortable from the outset. The Winter Skin Layer relies on a Circular Seamless construction that's free of irritating side seams. The sleeves are sewn directly into the armhole to promote a full range of motion beneath additional layers.

Maximum thermal protection and body-mapped comfort in a long-sleeved base layer, tuned for the coldest, most demanding winter riding conditions. Building on our protective Winter LS Skin Layer, the Ultraz edition turns up the warmth and windblocking capabilities even further with its wool-blended knit. We see this as the ultimate defensive first layer in the most challenging winter conditions, as it goes into overdrive at the core level to keep you dry and your temperature stable. A robust arctic-tuned blend of polypropylene and wool are employed, serving as the ultimate next-to-skin foundation when maximum thermal- and windblocking-protection are most critical. The Ultraz relies on a Circular Seamless construction that's both ultrasoft and free of irritating side seams. The sleeves are sewn directly into the armholes to promote a full range of motion beneath additional layers.

Maximum thermal protection and body-mapped comfort in a long-sleeved base layer, tuned for the coldest, most demanding winter conditions. Building on our protective Winter LS Skin Layer, the Ultraz edition turns up the warmth and windblocking capabilities even further with its wool-blended knit. We see this as the ultimate defensive first layer in the most challenging winter conditions, as it goes into overdrive at the core level to keep you dry and your temperature stable. A robust arctic-tuned blend of polypropylene and wool are employed, serving as the ultimate next-to-skin foundation when maximum thermal- and windblocking-protection are most critical. The Ultraz relies on a Circular Seamless construction that's both ultrasoft and free of irritating side seams, and the raglan sleeves promote a full range of motion beneath additional layers.