Diamond Theory Clothing
The London: White Mass Fit Shirt
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The Shirt
The Shirt
What is My Fit?
What is My Fit?
Diamond Theory has 2 Fits for shirts:
Muscle and Mass
- Muscle: This fit is designed with Bodybuilders in mind as this has an aggressive taper, bringing it right in at the waist.
- Mass: This fit is designed with Strongmen in mind as this has a less aggressive taper as Strength Athletes tend to have a thicker core.
Please take this as a reference and refer to the size guide with your measurements.
Sizing
Sizing
Check our Size Guide. Select the shirt most accurate to your measurements.
This shirt has been engineered from the ground up specifically for real athletes who carry real muscle and mass. Designed to drape and flow like a shirt should.
Before you order, please make sure you measure yourself and choose your size according to the size guide. Take your chest measurement and your waist measurement. No need to order a size down for a tighter fit.
Suggestion: If you are at the top of a size bracket, opt for the size up.
Shirts
For the Bodybuilders:

For the Mass Monsters:
Jerseys
Our Training Fit Size Guide:
Materials
Materials
premium, breathable cotton-blend fabric, the material offers a luxurious drape that flows effortlessly over muscle while maintaining structure. The result? A shirt that feels like it was custom-made, every time you wear it.
Shipping & Returns
Shipping & Returns
Free Shipping over £50
For returns please see returns policy for further detail
Care Instructions
Care Instructions
Wash on a low heat, air dry and press. Do NOT tumble dry.

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Free Shipping over £50