DEFINITION of 'Knuckle-Buster'

A manual credit card impression device. A knuckle-buster creates multiple copies of a credit card transaction by placing the credit card at the bottom of the device and blank carbon-paper on top, and then sliding a bar back and forth so that the embossed numbers on the credit card are copied on to the carbon-paper copies. This to and fro motion led to the device also being known in the credit card industry as a “zip-zap” machine. The equally colorful “knuckle-buster” term arose because frequent users of the device like retail store clerks and taxi-drivers often had to contend with skinned or callused knuckles due to the repetitive nature of the task.

BREAKING DOWN 'Knuckle-Buster'

The knuckle-buster’s biggest advantage may have been its portability. But that advantage is outweighed by its drawbacks. A common complaint is that the carbon copies generated by a knuckle-buster are often faint or illegible. Another common grouse is that the flimsiness of the carbon copy makes it prone to being destroyed unless handled carefully. Did we also mention skinned knuckles for frequent users?

But several trends are coming together to make knuckle-busters a thing of the past. Firstly, there are a rapidly growing number of payment options for transactions, all of which use new technology to verify and authenticate a transaction and the payer’s identity within seconds, making manual impressions an antiquated practice. Secondly, since the vast majority of transactions at the point-of-sale are either processed through card “swipes” or by the use of a personal identification number (PIN) for chip-and-PIN cards, embossed card numbers are becoming redundant. As a result, credit card companies now laser print – instead of embossing – details such as the cardholder’s name, card number and expiration date on the credit card. Finally, carbon copies are being phased out; one hardly uses them in any aspect of daily life, with the exception being the very occasional credit card transaction.