I went for size M due my previous Bambino Pro was sized L and needed to use gap under to provide tight enough feeling. I go for 58,5cm head circ. I found size M really SMALL. The physical size really is tremendously smaller than in size L. Even the visor touches my face. So If you ain't having a really small head circ (really under 58cm) I recommend going for size L. Needed to order a bigger size. Hope this info helps anyone else.