Sidewinder 20 (650 RDS DownTek) eclipse The CORE rechargeable battery offers

The CORE rechargeable battery offers an economical

Adding up to 4°C|7°F of warmth with minimal bulk

A low-profile elastic cinch at the top hem

its excellent weight-to-performance ratio means you can take it with you on different types of terrain like single pitch

A dialed-in precise fit makes for a sock that won't quit

Sidewinder 20 (650 RDS DownTek) eclipse The CORE rechargeable battery offersSpecifically designed for the over 60% of people who sleep on their sides, the second generation of our patented Sidewinder side sleeper technology ensures warmth, comfort, and ease of use in any position you settle into. Constructed for comfort, with additional body mapped insulation to optimize warmth where you need it and provide cushioning and support at the hips and shoulders, easing pressure points and other side effects. The Sidewinder is a