NMB is the standard skateboard bearing having been a staple item since day one.
Nippon Miniature Bearing Corporation (the present NMB Technologies Corporation) is established in Los Angeles, California. 1970's and as a go-to bearing were in existence prior to the invention of the Urethane wheel.
608z is the standard size for all skateboard wheels. The 608Z ball bearing is a single row raceway and single shield.
Bones Swiss, Bones Reds or Bones Big Balls are all great bearings but NMB is a standard go-to choice for any skateboarder.