adidas UltraBoost 21 - White - UK 8

The Primeknit upper offers a adaptable fit. While it stretches, individuals with significantly wide feet might find them snug. It's recommended to try them on if possible or consult sizing guides for a more precise fit assessment.

Your toes should not be pressed against the front of the shoe, and there should be a thumb's width of space between your longest toe and the shoe's end. The fit should be snug but not constricting around the midfoot and heel.

Yes, the UltraBoost 21 is designed with significant cushioning and energy return, making it suitable for marathon distances for many runners. Individual comfort and support needs may vary.

The UltraBoost 21 features an updated design with a more robust Boost midsole for enhanced energy return, a more structured heel counter, and often a slightly different upper construction compared to previous versions like the original UltraBoost.

The white color is made from durable materials, but like any light-colored footwear, it will show dirt more readily. Regular cleaning as per care instructions will help maintain its appearance.

No, the Primeknit upper is highly breathable but not waterproof. It is designed to keep feet cool and may allow water to pass through in very wet conditions.

Ensure you have chosen the correct UK size. The knit upper will offer some stretch over time, but if initially too snug, consider loosening the laces or trying a half-size up if available and the issue persists.

The Boost foam is designed for durability. If cushioning feels significantly reduced, it may indicate a need for replacement after extensive use, typically several hundred miles for running.

Check the Continental Rubber outsole for debris. Ensure the laces are tied securely. If the issue persists on wet surfaces, be aware that even high-traction outsoles have limitations.

Avoid contact with dark or dyed fabrics, especially when wet. Clean spills immediately with a damp cloth and mild soap.