Bank card vs Table tennis ball: size comparison
Bank card: 8.56 cm. Table tennis ball: 4 cm. Both silhouettes are drawn at the same scale.
Size ratio: ×2.1
Bank card
8.56 cm
What is measured Width of an ISO/IEC 7810 ID-1 card
Every bank card in the world is 85.60 × 53.98 mm.
Source : Wikipedia — IEC 7810
Table tennis ball
4 cm
What is measured Diameter of a table tennis ball
It grew from 38 to 40 mm in 2000 to slow the game down.
Source : Wikipedia — Table tennis