Abstract: A prepaid card is disclosed, which uses drawing codes not requiring so high accuracy and permits direct computer processing of read-out data without agency of any A/D converter, thus permitting system security improvement.In the prepaid card 1, main information 2, personal information 3, fingerprint image 4 and security data rotation key 5 are printed on the surface as a transparent print pattern with box drawing codes provided in the form of four tetrahedrons of different sizes arranged one inside another, the four sides of each tetrahedron being constituted by respective segments representing respective bit expressions, the individual bit expressions of the segments being for a predetermined digit place arrangement from the least significant digit place to provide a binary number system expression representing a corresponding decimal or n-step number system expression, a predetermined numeral, character, symbol, etc.

Abstract: A pull tab type opening device is formed upon an insert metal strip mounted atop the can's lid. The opening device is affixed to and covers an opening in the can's lid by inter-locking rim portions on the strip and lid. Accordingly, the lid may be formed of a less expensive metal, such as steel, while the metal strip, occupying a small portion of the lid, is formed of the more expensive aluminum. Since the percentage of the dissimilar metal, aluminum, in a can is very small in comparison to steel, a used can may thereby be processed as a single metal, steel.