The information stamped into the bottom of a Hot Wheels car shows key design and manufacturing dates for each particular model. The imprint also contains brand and manufacturer logos.
There are two key dates imprinted on the underside of Hot Wheels cars. One is shown as a copyright and represents the first year that this particular model was approved for production. The other date usually is stamped on the bottom as a letter with a number behind it -- this is the actual date of manufacture. The letter shows the year, based on the copyright date of the car. The number is the week during that year that the car was cast and produced.
The Hot Wheels official logo and the Mattel corporate logo are also imprinted on all Hot Wheels models. Their presence certifies the cars as authentic for collectors.