Kensington Security Slot
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The Kensington Security Slot (also called a K-Slot or Kensington lock) is an anti-theft system for hardware electronics such as notebook computers, computer monitors and others. It is a small, metal-reinforced hole used for attaching a lock-and-cable apparatus. It is produced by Kensington Computer Products Group.
Development
Designed in the mid 1980s<ref>Template:CitationTemplate:Cbignore</ref> and patented by Kryptonite in 1999–2000,<ref name="KryptonitePatents">Security anchor/tether assemblage for portable articles: Template:US patentTemplate:US patent and Template:US patent (Cornelius McDaid, John Ristuccia, Kryptonite Corporation - priority date: 1999-06-21)</ref> assigned to Schlage in 2002, and since 2005 owned and marketed by Kensington Computer Products Group.<ref name="SAFE" />
Design
Kensington created a slot-based locking mechanism in 1992<ref> Raji Sahota. "Kensington Enhances Hardware Security for Those Returning to Office". </ref> very similar to ones Jay S. Derman had patented earlier; eventually leading to Kensington and ACCO Brands acquiring those patents and keeping him on as a designer.<ref name="ernie_smith"> Ernie Smith. "What’s the Deal With That Security Slot on Your Laptop, Anyway?". 2021. </ref>
The system consists of a small, metal-reinforced hole found commonly on small or portable computers and electronics equipment such as laptops, computer monitors, desktop computers, video game consoles, audio interfaces, and video projectors, combined with a metal anchor attached to a rubberized metal cable secured with a key or combination lock. The end of the cable has a small loop that allows the cable to be looped around a permanent object, such as a heavy table or other similar equipment.<ref name=KryptonitePatents/>
The hole is found in many laptops, although a lock for it is typically not included. Occasionally, the slot is located so that installing a lock will also prevent the removal of a valuable subcomponent, such as a rechargeable battery or a memory module. The Kensington slot may be marked with a small icon that looks like a padlock with a capital "K", or the slot may be unlabelled.
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For many years, 95% of all laptops were manufactured with a Kensington slot.<ref name="ernie_smith"/><ref name="invue"> "Laptop Security Locks for Devices Without Kensington Slots". 2025. </ref>
Efficacy
Kensington locks can discourage opportunistic grab-and-run thefts of equipment from public locations such as coffee shops or libraries, but they are not designed to be impervious protection measures, nor are they intended to secure equipment in unattended locations,<ref name="SAFE">Template:Cite web</ref> because they can be torn out of equipment (although not without causing visible damage), given that the cases are typically made of plastic or thin metal, and the cable can be cut with wire or bolt cutters. In addition to this, successfully securing the non-locking, loop end of the cable is dependent upon the availability of a suitable anchoring point on a virtually immovable base object, or a thief may just shift that object, and then take the protected device with cable attached.
The lock mechanism is typically a tubular pin tumbler lock or, less frequently, a flat key lock or a numeric combination lock with no key.<ref name="SAFE" />
Alternatives
As laptops have gotten thinner, many no longer have the space above and below the "long side" of the 7 mm x 3 mm security slot required for the original Kensington security lock.<ref name="invue" /><ref name="kss_vs_knss"> "Kensington Security Slot vs. Nano Security Slot: What’s the Difference?". 2021. </ref><ref name="jari_turkia" > Jari Turkia. "Post-passwords life: Biometrics for your PC". 2022. </ref>
There are at least 2 alternative slot-based locking mechanisms that fit much thinner laptops, where the lock does not extend above or below the "long side" of the security slot, but instead extends left and right behind the "short side" of the security slot:
The Kensington NanoSaver Laptop Lock fits into a Kensington Nano Security Slot.<ref> Kensington press release. "Kensington NanoSaver Locks Secure the Next-Generation of Ultra-Thin, Lightweight Devices". 2023. </ref> Some Lenovo ThinkPads, HP laptops, and ASUS laptops are manufactured with a 6 mm x 2.5 mm Kensington Nano Security Slot.<ref> "ThinkPad T14 Gen 3". </ref><ref name="kss_vs_knss" /><ref name="jari_turkia" />
Newer Dell laptops are manufactured with a 4.5 mm x 3.2 mm Noble Wedge-Shaped Security Slot.<ref name="jari_turkia" /><ref> Avram Piltch. "Laptop Lock Buying Guide: 5 Things You Need to Know". 2016. </ref><ref> Dell. "Noble TZ04T Cable Lock For Notebook". </ref><ref> "The Noble Locks Wedge slot". </ref>
Several manufacturers offer similar locking mechanisms that do not require a special lock hole.<ref>Template:Cite web</ref> They attach to a popular port, such as the VGA or printer port, and have special screws to secure locks in place.