NN type: inner ring have three integral flanges, outer ring without flange NNU type: outer ring have three integral flanges, inner ring without flange.

These can be made with cylindrical bores.
Or tapered bores as standard, the suffix K means bore taper 1:12, the taper bores allow the radial internal clearance to be adjusted to the best value during mounting. These bearings also feature lubrication groove and holes on their outer rings as standard.

Misalignment
Double row cylindrical roller bearings are not able to accommodate misalignments.
Tolerance Double row cylindrical roller bearings are frequently used as spindle bearings, normally they ate produced to special tolerance class SP.