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VIPER 640 M-8 MAINSAIL

Marsoni M251S
Sale price$1293.50
Pay 4 payments of $323.38 a month.Shop Pay
Get it in 3 business days with 1 day shipping. Friday, May 29
VIPER 640 M-8 MAINSAILThe M8 is an update to our tried and true M7 the winningest Mainsail in class history with Multiple World and Continental Championships. With a proven shape that delivers unparalleled top end speed and a forgiving twist profile, the M8 is built from our proprietary North XI laminate cloth. The forgiving nature of this sail makes it easy to get up to speed and stay there!
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Your VIPER 640 M-8 MAINSAIL orders ship within 1-2 business days.

Delivery Options:

  • Standard: 3-7 business days
  • Fast: 2-3 business days
  • Express: 1-2 business days

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You'll receive a tracking link by email once your VIPER 640 M-8 MAINSAIL ships.

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Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
4.7 ★★★★★
Based on 2181 reviews
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Darrah
Draper, US
★★★★★ 5
Great socks
Size: Large, Color: (672) Super Pink / Blaze Orange / Super Pink
My favorite socks! Fit great and don’t slip down in my shoes. They are cozy and cushiony. I love the colors too.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on October 21, 2025
C
Verified Purchase
Crystal slater
Fort Morgan, US
★★★★★ 5
Quality under armor product
These are so very comfortable they are thin yet keep my feet warm around the house while it’s snowing outside
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 7, 2026
L
Verified Purchase
Lindsey K
Carnegie, US
★★★★★ 5
Fav socks
My favorite socks! Love them!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 20, 2026
D
Verified Purchase
Dawn
Lake Worth, US
★★★★★ 4
Not bulky fit
Size: Large, Color: (009) Gray Dawn / White / Prime Pink
Thinner than UA other cushioning run socks, but this fit is perfect and doesn't shift in my shoe. I wear a women's 9.5 and determined Large doesn't squeeze my foot like Medium size (too exact). Bonus... avaliable olors beyond black and Grey.
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Reviewed in the United States on October 2, 2025
C
Verified Purchase
Cynthia Chouinard
Lexington, US
★★★★★ 5
Comfortable
These are very comfortable to wear
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 3, 2026

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