According to the size guide, I should wear a medium. It was W-A-Y too big and simply couldn't get a snug fit. Had to order a small. Now that it fits properly, i like it a lot!
The Lazer was highly rated by Virginia Tech so I took a chance. Unfortunately the helmet kept sliding on the back of my head exposing my forehead. I tried every adjustment and adding some foam to the back of the helmet to better secure and tighten down. The chin straps seem to be not be well positioned for a proper fit. I looked like Primoz Roglic on his TdF time trial in 2020. Returned the Lazer for a better fitting Giro Cinder.