The Arc'teryx Phase SL Zip Neck is a silkweight baselayer made from 100% polyester Phasic SL fabric using advanced performance technology. Features a next-to-skin fit with anatomical shaping, a deep front zipper, a tall collar, and gusseted underarms. It weighs approximately 110 grams. The SL designation means "Superlight" - the lightest option in Arc'teryx's Phase line. Mechanical stretch provides unrestricted mobility. Encapsulated silver ion fibers provide odor control. UPF 25 sun protection. Price approximately $75-85. Best for high-output activities with stop-start intervals.
How Does the Phase SL Zip Neck Fit?
The Phase SL Zip Neck features a next-to-skin fit that maximizes thermal efficiency and moisture transfer. The tight fit ensures fabric sits directly against skin for optimal wicking performance during high-output activities. Arc'teryx updated style lines provide improved fit over previous versions.
The anatomical shaping follows the body's contours for greater comfort during movement. Gusseted underarms facilitate ergonomic freedom without restriction. The mechanical stretch textile enables unrestricted mobility across the full range of motion. Flatlock construction improves next-to-skin comfort by reducing seam bulk and eliminating chafing points. Sizing runs true to Arc'teryx standards. The next-to-skin fit requires accurate sizing - too loose compromises moisture management, while too tight restricts movement during active use. I typically layer the Phase SL under something thicker for cooler conditions that require more insulation while maintaining breathability.
Is the Phase SL Warm Enough?
The Phase SL provides minimal insulation as a silkweight baselayer designed for high-output activities. The lightweight construction prioritizes moisture management over warmth. The 110-gram weight classifies it as ultralight, suitable for cool to mild temperatures.During active phases, the fabric wicks moisture across the entire surface, aiding temperature regulation. The tall collar adds modest neck warmth. The deep front zip enables rapid ventilation when overheating.
For a serious cold, the Phase SL works best as a moisture-wicking layer under warmer baselayers. The silkweight construction excels in shoulder seasons and high-output winter activities where sweat management matters more than insulation.
How Fast Does It Dry?
The Phase SL excels in rapid drying - its primary design purpose. Next-generation Phasic SL yarns speed dry times through advanced moisture dispersion. During stop-start activities, moisture that is broadly dispersed evaporates quickly upon entering rest phases, preventing chilling. The 100% polyester dries significantly faster than merino wool or cotton. The silkweight fabric contains minimal material, which helps retain moisture. The moisture-wicking technology pulls sweat from the skin and spreads it across the garment's surface for accelerated evaporation.
Reviewers note quick-drying as a standout feature. The Phase SL handles environments where quick drying proves essential - water sports, heavy sweating, humid conditions, and varying intensity activities. The Arc'teryx Rho LT Bottom completes a full baselayer system optimized for moisture management.
Does It Control Odor?
Yes, the Phase SL features encapsulated silver ion fibers that provide durable odor control. The silver ion technology works continuously throughout the garment's lifespan. The antimicrobial properties inhibit bacterial growth that causes odor in synthetic fabrics.
The odor control enables multi-day use without washing during backcountry trips. Reviewers reportthat the Phase SL maintains freshness better than untreated synthetics. The technology performs well during high-output activities, generating significant sweat. The 100% polyester without silver treatment would develop odor quickly. The encapsulated silver ions distinguish the Phase SL from basic synthetic baselayers.
How Durable Is the Phase SL?
The Phase SL sacrifices some durability for weight savings. The silkweight construction shows wear faster than heavier baselayers. Mechanical stretch without spandex improves durability compared to elastane-based fabric, which degrades over time.
The flatlock construction and Merrow stitch reduce seam size while maintaining strength. The next-to-skin fit minimizes abrasion from outer layers. Users report the Phase SL lasting multiple seasons with regular use. The lightweight nature requires careful handling - sharp objects and rough surfaces create snags more easily. The fabric maintains moisture-wicking capabilities throughout its lifespan without degradation.
Is the Arc'teryx Phase SL Zip Neck Worth It?
The $75-85 price positions the Phase SL competitively for premium synthetic baselayers. For users prioritizing rapid drying and minimal weight during high-output activities, the Phase SL delivers excellent value. The Patagonia Capilene Cool Lightweight Zip Neck offers similar quick-drying performance at a comparable price, made from recycled polyester. The Smartwool Merino 150 provides natural odor control at similar cost with slower drying.
The Phase SL's advantages include the lightest weight in the category, excellent moisture dispersion, and reliable odor control. The sil,kbut dries moreslowly, is for specific use cases - stop-start activities in cool conditions where rapid drying prevents chilling. Check Arc'teryx's website for current availability. The Phase SL represents the lightest, fastest-drying option in Arc'teryx's Phase baselayer lineup.
