Filson Men's Baselayers

Frequently Asked Questions

• What materials do Filson men's baselayers use, and what do the different weights mean?

  Filson baselayers use 100% ultrafine merino wool (18.5‑micron) in weights like 230g, 280g and the expedition‑weight 400g, plus a 12‑oz Peruvian cotton waffle knit in the Waffle Knit Thermal Crew. Lighter merino (230–280g) is versatile for active layering, while the 400g merino is built for subfreezing, stop‑and‑go work; the cotton waffle is best for dry, casual warmth and breathability.
• When should I choose the 400g Merino Wool Long Sleeve Half‑Zip and 400g Merino Wool Bottoms?

  Pick the 400g Merino Wool Long Sleeve Half‑Zip and 400g Merino Wool Bottoms for frigid expeditions, icy river wading under waders, or prolonged exposure to cold and wet conditions where insulation when damp matters. The 400g knit traps more air for insulation, resists odor, and retains insulating properties when wet, making it better for low‑temperature, variable‑activity use than lighter baselayers.
• How should Filson baselayers fit and do I need to size up or down?

  Filson uses a classic, roomy fit designed to layer over thermals and under shells; US sizing runs on the roomier side. If you prefer a closer next‑to‑skin fit for layering, consider sizing down one size from a loose European fit; for reference, a Medium is commonly shown on models around 1.89 m / 93 kg.
• How does merino compare to the Waffle Knit Thermal Crew for outdoor activities?

  Merino (230g–400g) offers superior moisture management, natural odor resistance, and retains insulating properties when wet, so it’s the better choice for wet, cold, or multi‑day outdoor use. The Waffle Knit Thermal Crew (12‑oz Peruvian cotton) provides a breathable, air‑trapping texture that feels soft and durable for dry, casual wear or lower‑sweat activities, but cotton won’t insulate as well when damp.
• What construction details and care steps keep Filson baselayers comfortable and long‑lasting?

  Filson baselayers use flatlock seams to reduce chafing, ribbed cuffs and collars, an elastic waistband with front fly on bottoms, and dense merino knits that trap air for warmth. Care per garment tags—machine wash cold on delicate and tumble dry low or lay flat to dry—helps preserve fiber softness and fit while maintaining the flatlock seams and knit structure.