The dimensions of our floating battery bushing may be viewed on the part drawing.
As lead-acid batteries age, positive plate growth occurs which will cause the positive terminal post to expand upward. As a result, this can distort the top of the battery case and cause it to bulge upward. This can ruin the battery if it cracks the cover or breaks the seal.
To prevent this, some companies install a floating lead bushing instead of attaching the terminal post directly to the cover. The floating lead terminal bushing prevents the plate growth from warping the top of the battery by growing upward along with the lead post.
This bushing may be compared to a piston that is free to move up and down in a cylinder bore. Just like piston rings that seal against the cylinder wall, the rubber o-rings on the bushing maintain the seal against the battery cover as the positive plates grow due to aging.