What size does it come in?

The size of the Matrix and Street helmet is 56 – 61 cm (approx. 22 - 24 inches). Please note that if you add MIPS to your helmet, it will lower the available circumference by maximum 1 cm.

Matrix and Street are designed with a wider shell to accommodate a broader range of head shapes and sizes. 

To get the right fit for your helmet, you can read this article.