Abstract: Kidney-shaped push up insert including first lobe and second lobe is provided. Notch is formed in top side between first lobe and second lobe. Insert has depression formed adjacent top side extending towards notch. Second main surface opposes first main surface. Second main surface is substantially smooth arcuate-shaped surface. First lobe has narrower width between top side and bottom side than second lobe, and second lobe is thicker between first main surface and second main surface than first lobe. Ratio of maximum thickness between first main surface and second main surface to maximum length between opposing ends of first lobe and second lobe is less than about 9 and/or ratio of depth of notch from a straight line connecting first lobe and second lobe along top side of insert to width of insert from top side to bottom side at depth of notch is less than about 4.

Abstract: Kidney-shaped push up insert including first lobe and second lobe is provided. Notch is formed in top side between first lobe and second lobe. Insert has depression formed adjacent top side extending towards notch. Second main surface opposes first main surface. Second main surface is substantially smooth arcuate-shaped surface. First lobe has narrower width between top side and bottom side than second lobe, and second lobe is thicker between first main surface and second main surface than first lobe. Ratio of maximum thickness between first main surface and second main surface to maximum length between opposing ends of first lobe and second lobe is less than about 9 and/or ratio of depth of notch from a straight line connecting first lobe and second lobe along top side of insert to width of insert from top side to bottom side at depth of notch is less than about 4.

Abstract: Kidney-shaped push up insert including first lobe and second lobe is provided. Notch is formed in top side between first lobe and second lobe. Insert has depression formed adjacent top side extending towards notch. Second main surface opposes first main surface. Second main surface is substantially smooth arcuate-shaped surface. First lobe has narrower width between top side and bottom side than second lobe, and second lobe is thicker between first main surface and second main surface than first lobe. Ratio of maximum thickness between first main surface and second main surface to maximum length between opposing ends of first lobe and second lobe is less than about 9 and/or ratio of depth of notch from a straight line connecting first lobe and second lobe along top side of insert to width of insert from top side to bottom side at depth of notch is less than about 4.