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Serious Mass by Optimum Nutrition

Marsoni M251S
Sale price$149.95
Pay 4 payments of $37.49 a month.Shop Pay
Get it in 3 business days with 1 day shipping. Friday, May 29
Serious Mass by Optimum NutritionOptimum Nutrition Serious Mass: the ULTIMATE in weight gain formulas. Optimum Nutrition Serious Mass supplies you with the tools you need to pack on the pounds and develop the physique you've always wanted. Super high in carbohydrates and Calories Optimum Nutrition Serious Mass is designed to help trainers with fast metabolisms obtain the calories they need to gain weight. 1,250 Calories per serve. 50g of blended protein. Over 250g of Carbohydrates
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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]
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4.2 ★★★★★
Based on 110 reviews
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Verified Purchase
Kevin Boynton
Grantham, US
★★★★★ 5
Works
Fit my 1996 xr6 150 just fine. Engine runs at correct temperature so they are working as they should.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 13, 2026
C
Verified Purchase
Champ
New York, US
★★★★★ 5
Quick delivery
Fit like they should and seems to be working great
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 15, 2026
G
Verified Purchase
GINGER B.
Waukegan, US
★★★★★ 5
Great product
Great product
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Reviewed in the United States on December 30, 2025
C
Verified Purchase
chris s
Boise, US
★★★★★ 5
Fit Mercury 150 saltwater 2 stroke great!
These fit my Mercury 150 perfect. Took it out for a test run and engine ran great with no overheating issues.
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Reviewed in the United States on August 26, 2025
R
Verified Purchase
Robert Werkhoven
Lowell, US
★★★★★ 5
Work’s okay
They work ok, as expected
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Reviewed in the United States on August 26, 2025

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