219KD Shielded Radial Ball Bearing Outer Diameter - 1 11/16 inch (1.6875") the 6308ZZENR inner diameter is

the 6308ZZENR inner diameter is 40mm

As stated by the description

SM120UU Bearing

Size: 70 x 125 x 26

4 Linear Ball Bushings

219KD Shielded Radial Ball Bearing Outer Diameter - 1 11/16 inch (1.6875") the 6308ZZENR inner diameter is219KD Deep groove ball bearing single row Radial Bearing 95x170x32 219KD Deep groove ball bearing single row Radial Bearing 95 mm ID x 170 mm OD x 32 mm Wide. Item Sku : 219KD Brand : VXB Type : Deep groove ball bearing Inner (ID) : 95mm Outer (OD) : 170mm Width : 32mm Inner Inch : 3. 74 Inch Outer Inch : 6. 693 Inch Width Inch : 1. 26 Inch Size : 95mm x 170mm x 32mm Size Inch : 3. 74" x 6. 693" x 1. 26" Dynamic load : 114 kN Static load : 81. 5 kN