They are high speed bearings not unlike the ones used in a lot of front wheel hubs. You can get the ones with the snap rings from GoPowerSports for a decent price.
The snap rings are there to help with the spacing on the bearings as on the jackshaft tube and many front hub assemblies you will find that there is not a shoulder for the bearing to index against. This prevents the bearing from falling all the way into the assembly or tube if you understand my meaning.
Don't cheap out on your bearings. But don't overpay either. 3-4 bucks at most.