Our 6806 open bore adapter is used to press 42x30 sealed bearings. The adapter is machined with one step at 30mm ID, which fits into the center of the sealed bearing. Common bearing size for BB30 frames and bottom brackets. - Installs: 6806 bearing - Inner step outer diameter: 29. 9mm - Outer diameter: 41. 8mm - Thickness: 7mm - Thru hole diameter: 0. 387" (9. 8mm) - Inner hole sized to fit 1/2" threaded rod - Compatible BP0006, BP0007 - Machined, red anodized aluminum - Sold individually (2 drifts required for some installations)