What does ABEC mean?
The number after ABEC indicates how fine the rolling element is. The rolling element in a ball bearing is usually made of balls (makes sense) and reduces the friction between the wheels and the axle. Many people think that only the number behind ABEC is relevant.
But this is only partially true. Although finer rolling elements are quite suitable for fast driving, they are more susceptible: the higher the number, the more susceptible. The overall picture is decisive. If the rolling elements are tiptop but the rolling bearing is not, it is just as ineffective as a car that can go fast but whose tires are square. With the help of the brand you can check the quality.
Just about every skater has heard of the brand Bones. Their ball bearing is called REDS. A universally popular ball bearing. Yet probably not even half of them know which ABEC level it has. As you can see now, the brand is sometimes very important. What to do if there is no brand available. Hands off! Either because it was not mentioned for a good reason or because it is so unknown that even the board manufacturer does not know it.
In principle the number should not be less than 5. So if you want to buy a cheap penny board or a pair of adult roller skates in the future, you should make sure that the bearings are from a good and well-known brand and ask the manufacturer if the brand is not listed. Also, the step should not be smaller than 5! Have fun skating.