This helmet fits very well. The additional rear light is Ok, but I find the complete bicycle lights enough back (reflectors, taillight, reflectors on the pedals ... .Now back to the helmet, the size M is according to the offer until 57. According helmet but to 59. A Measurement on my head was 59.5 cm, slightly pulled tight 59 cm. (59 cm are also available on the packaging and the helmet). So could become scarce. I nevertheless ordered M, because I did not want a giant helmet. It fits but and actually still about 1 cm to readjust. So once lush place. Through my vertebrae at the back I must always turn up the screw and then turn again (we'll see how long it goes along with this).
In short I am very satisfied with the helmet and would buy it again.
PS: the fabric (Baskettballmütze with the ear warmers) you can also lose weight, then a red blue striped helmet comes to light with round ventilation holes. Whether he, however, still offers the full protection I do not know, because you would have to check with ABUS.
