608ZZ is used in consumer motors such as fans and blowers. Most of the 608 bearings available from Revain are "Skateboard Certified" which means they are manufactured to wide tolerances and use rubber seals. This means if you use a 608 skateboard with an electric motor you will get a lot of noise and reduce bearing life. These bearings meet the 608ZZ standard, are manufactured to tight tolerances and are metal sealed. The tolerances are so tight that you have to scrape rust off the motor rotor shafts to get the bearings to fit, which is good, it shows that these bearings are machined to tight tolerances. A low tolerance bearing is a quiet bearing. I use 608 to rebuild fan motors and they are sometimes even quieter than new originals! If you need 608ZZ for electric motors, you'll be hard pressed to find a lower-priced bearing than Xike. They even come packaged in a box and foam insert, which really shows that the manufacturer cares about their product. I will recommend and buy again.