Kask motocyklowy and other 84,100 icons from Icons8 icon pack follow the visual guidelines of the operating systems: Windows, iOS, Android KitKat, and Material. PNG format is free up to 100x100 px. Icons are availble for download in PNG and vector (SVG, PDF, EPS, and more).
It is the outline of a helmet as seen from the right side, in profile. A circle and a dot in the center represent where the visor meets the helmet, and there is an outline representing the visor as well.