Made for abec 9 berings
you should probally use some kink of glue to put them in.
you can get the berings here:
https://www.amazon.com/CJESLNA-Bearings-Skateboard-Longboard-101005003128/dp/B00BUH45DU/ref=sr_1_2?s=sporting-goods&ie=UTF8&qid=1495113409&sr=1-2&keywords=abec+9+bearings