These high precision 608ZZ skateboard bearings (also known as 608, 608-2RS, 608-ZZ, 608-2Z & 608 ZZ) provide high speed and can also be supplied with removable shields for cleaning and re-lubrication. Higher grades are also available from stock although these are generally used on high speed electric motors and high speed vacuum applications.
Priced accordingly, whilst they are not cheap you'll be safe in the knowledge that your board has the best 608 money can buy.