Whether the sun is going down, or just hasn&';t come up yet, the Sundown 250 1/2 Zip rises to the occasion. A familiar waffle-knit structure, which has always been a go-to for offering superior warmth, in the lightest and most packable package. A staple component of A/SYS-2, the Sundown is super-charged with Nuyarn merino Technology, so you won&';t care if the sun ever comes up. A Features Superior BluesignA(R) 250GSM Nuyarn merino offers extra loft for an unmatched warmth-to-weight ratio 5x faster drying Remarkable long-term durability Superfine 18 micron non-mulesed Australian merino Wool for maximum softness and wearability Incredible stretch and recovery Slim Tech Fit for maximum movement Targeted waffle and flat Nuyarn fabric placements for less weight and more warmth No-chafe flatlock seams Gusseted underarm Hang-Dry loop YKK Zippers Zip kangaroo and hand pockets