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Knuckle-Buster is a slang term referring to a manual credit card imprinter used to process credit card transactions. Before electronic payment systems, merchants used these devices to create a physical imprint of the customer’s credit card on carbon-copy sales receipts. They were called Knuckle-Busters due to their shape and the potential for the user’s knuckles to be injured while sliding the imprinter back and forth.


The phonetic pronunciation of “Knuckle-Buster” is: /ˈnʌkəlˌbʌstər/

Key Takeaways

  1. Knuckle-Buster is a term often used to describe a manual credit card imprinter, which is a device that creates a physical imprint of a customer’s credit card, providing a record of the transaction.
  2. Manual credit card imprinters were popular before the widespread use of digital technology and electronic card readers. Many businesses still use them as backup systems in case of electronic equipment failure or for transactions in remote locations without internet access.
  3. Using a Knuckle-Buster typically involves placing a multipart sales slip, the credit card, and the imprinter itself in the proper alignment. The user then swipes or slides the handle across the card and slip, creating an imprint of the card details. The merchant and customer each receive a copy of the sales slip as proof of the transaction.


The term “Knuckle-Buster” holds significance in the business and finance world as it refers to an outdated yet crucial manual credit card imprinter used by merchants for processing transactions. In the absence of electronic payment processing systems or during technical glitches, the Knuckle-Buster enabled merchants to continue accepting credit card payments. The name derives from the potential risk of jamming or pinching the user’s knuckles while operating the device to create a physical imprint of the customer’s credit card details onto carbon paper receipts. Despite being antiquated, this device highlights the importance of having reliable and adaptable transaction methods, reminding contemporary businesses that flexibility, innovation, and adaptability are key in developing technologies to handle financial transactions efficiently.


A knuckle-buster, more formally known as a manual credit card imprinter, is a specialized device used predominantly by merchants to process credit card transactions without the need for electronic card readers or internet connectivity. Employed primarily during the early days of credit card usage, or even today as a backup during electronic transaction equipment failure, the knuckle-buster earns its colloquial name due to the required sliding motion that sometimes results in users injuring their knuckles. This manual device made it possible for merchants to generate a physical imprint of the customer’s card, thus establishing a proof of sale, as well as enhancing the security of credit transactions.

During a transaction, the merchant places the customer’s credit card between layers of carbon paper, which has the sales slip on top, and then the knuckle-buster’s handle is slid across the card, creating an imprint of the card’s raised numbers and name on the sales slip. The customer and merchant each retain a copy of the slip, and the merchant later deposits the sales slips at their financial institution for transaction settlement. Although the use of knuckle-busters has largely been replaced with digital card readers thanks to advancements in technology, some businesses in remote areas or traditional vendors might still use them as an economical and reliable alternative, ensuring the continuity of sales processing even when network services are not available.


A knuckle-buster, also known as a manual credit card imprinter, was a tool commonly used by businesses before electronic point-of-sale (POS) systems were widespread. It allowed merchants to make a physical carbon copy of a customer’s credit card. Here are three real-world examples of where you might have found knuckle-busters being used:

1. Small Retail Stores: Before electronic payment systems became prevalent, small retail shops often used knuckle-busters for credit card transactions. When a customer wanted to purchase an item using a credit card, the shopkeeper would place the card in the imprinter, together with a multi-part carbon sales slip, and slide the handle back and forth, creating an imprint of the card details. The shop would keep a copy of the slip for their records, and the customer would sign a copy for authorization.

2. Restaurants: Before the portable electronic card readers, restaurants would use manual credit card imprinters to capture customer card information. If a diner wanted to pay for their meal with a credit card, the waiter or waitress would take the card to the payment station, use the knuckle-buster to process the transaction, and bring the physical slip back to the table for the customer to sign.

3. Outdoor Markets or Flea Markets: In situations where access to electricity and phone lines was limited or unavailable, such as at outdoor markets or flea markets, vendors often relied on knuckle-buster. With the manual credit card imprinter, these merchants were able to process credit card transactions without having to be connected to an electronic transaction system.

Frequently Asked Questions(FAQ)

What is a Knuckle-Buster?

A Knuckle-Buster is a slang term for a manual credit card imprinter, a device used by merchants to process credit card transactions before electronic point-of-sale (POS) systems became widespread. They earned their nickname because they often caused strain on users’ hands and occasional injuries while processing transactions.

When were Knuckle-Busters commonly used?

Knuckle-Busters were widely used before the introduction of electronic POS systems, primarily in the 20th century. Although they are now considered outdated technology, some businesses still use them for backup purposes when electronic systems are not available or as an alternative for processing credit card transactions without electricity.

How does a Knuckle-Buster work?

A Knuckle-Buster has a flat surface with a clamp-like mechanism used to hold a credit card in place. When the card is secure, a merchant places a carbon multipart sales slip over the card and runs a roller across the device, which imprints the card information onto the sales slip. The customer then signs the slip, and a copy is given to both the merchant and customer as a receipt.

Are Knuckle-Busters still relevant today?

While electronic POS systems and online payment gateways have largely replaced manual credit card imprinters, some businesses still use Knuckle-Busters as a backup for processing transactions when electronic methods fail or are unavailable. They can also be useful for mobile businesses, such as food trucks or market vendors, that might not have consistent access to electricity or internet.

Are there security concerns with using Knuckle-Busters?

Yes, since a Knuckle-Buster relies on physical copies of credit card information imprinted on sales slips, the risk of sensitive data exposure is higher compared to electronic payment methods protected by encryption. Merchants using Knuckle-Busters should take precautions to secure carbon copies of the sales slips and dispose of them properly to minimize the risk of unauthorized access to customer information.

Can businesses still purchase and use Knuckle-Busters?

Yes, manual credit card imprinters, or Knuckle-Busters, can still be purchased through some vendors, and businesses can use them as an alternative method for processing credit card transactions. However, many businesses have opted for electronic POS systems due to their efficiency, security, and ease of use.

Related Finance Terms

  • Manual credit card imprinter
  • Merchant processing
  • Sales draft
  • Chargeback
  • Payment authorization

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