Made by Boca Bearing, the ceramic 40mm axle bearing spins freer and basically lasts forever. Part number UC208C-40MM non-removable seal.

Bearing info:

Bearing Material Chrome Steel 52100

Rolling Element Mat. Ceramic SI3N4

Dimension Type Metric ID (d) 40 OD (D) 80

Width Inner Ring 49.2

Width Outer Ring 20

Insert Type Spherical-Curved OD

Locking Type Set Screw

Enclosure # Two Seals

Enclosure Material Chrome Steel

Enclosure Type Contact Seal

Retainer Material Chrome Steel

ABEC/ISO Rating ABEC#1/ISOP0