Which tool is commonly used for blending hair during a haircut?

Thinning shears are specifically designed to create texture and blend hair effectively during a haircut. Unlike regular scissors that cut hair straight across, thinning shears have a unique design with one blade containing teeth. This allows them to remove some bulk from the hair while maintaining length, resulting in a softer, more blended appearance. This technique is particularly beneficial when transitioning between different lengths or in layers, as it helps to eliminate harsh lines and promote a more seamless look.

In contrast, the other tools have different specific functions. A razor is primarily used for creating softer, wispy edges and can be effective for layering, but it doesn't blend hair in the same way that thinning shears do. A comb is essential for sectioning and managing hair but does not cut hair itself. Clippers are typically used for cutting shorter hairstyles or for creating precise lines and fades, not for blending purposes. Thus, thinning shears are the most suitable tool for blending hair during a haircut, making them the correct choice in this scenario.