|This article requires photographic illustration — needs illustrating further using disassembly shots, from other pages|
A slider is in keyboard terms a plunger that slides downwards when the key is pressed, and vice versa in the other direction when the key is released. Not all plungers are sliders - sliders are restricted by guide-rails or by the walls of a tight-fitting shaft. A plunging-shaft that is cylindrical is often called a barrel. Another common word for plunger is stem (especially in Cherry terminology) although it is more helpful to use "keystem" to refer to the shaft atop the slider onto which the keycap is placed (something that many sliders do not have).
Most keyboard switch mechanisms contain a slider. A slider can be integrated into the bottom of a keycap or have a keycap mount on the top side. Most mechanical keyboard switches have the sliders locked into discrete switch components while most rubber dome switches have the sliders in the bottoms of the key caps.
A key could have one or more secondary sliders for stabilising a key, often as a complement or a cheaper alternative to a stabiliser bar. Sliders are sometimes also used for connecting keycaps to stabiliser bars hidden inside a keyboard.
With some switches the colour of the slider/stem is significant in telling the variation of the switch.
For instance, the colour of an Alps SKCL/SKCM series switch's slider suggests what force curve is used. For example green sliders typically indicate linear switches, while blue sliders are always found in clicky switches. Acer switches resemble Alps switches and came with both white and black sliders, but the colour of the slider has no known significance.
For all current production Cherry MX switches, the colour of the stem guarantees the force curve of the switch, and whether audible feedback is provided. For example brown signifies 45 cN tactile while blue signifies 50 cN clicky. Some older switches lack pigmentation; a colourless slider could be Cherry MX Clear, but it could also be one of several other switches, including Cherry MX White if the slider has a cam to denote hysteresis.
The blue slider in the Cherry MX Blue switch signifies the MX1A-E1xx family of 50 cN clicky switches
Cherry MX sliders and springs
Switches with white sliders can be referred to as "white" or "clear" depending on the brand. With Cherry switches, "white" refers to sliders with white pigmented plastic, while in most other cases, "white" refers to unpigmented, colourless plastic. Cherry describe colourless plastic as "clear", which may allude to its subtle translucency and reduced reflectiveness.
Use with dome switches
Rubber dome switches require a stem that extends from the top of the keycap down to the top of the dome, which is used to depress the dome. In most cases the stem is a slider that is part of the keycap, but many rubber dome keyboards are fitted with discrete sliders. Topre continues this practice today.
One example is the AppleDesign Keyboard model M2980, which came in variants with either discrete sliders or with the sliders in the bottom of the keycaps.
The interface between the keycap and the switch is called the keycap mount. Two widely used mounts are called "Cherry MX Mount" and "Alps mount", as used by Cherry and Alps respectively. Numerous types of switch including Alps SKCL/SKCM series, the Acer switch and the Monterey switch all share the "Alps mount", as do some rubber dome keyboards; the keycaps of these switches are fully interchangeable. There are also rubber dome keyboards that use the "Cherry MX mount" via sliders, and will consequently take keycaps designed for Cherry switches.
Packard Bell 5149 rubber dome keyboard demonstrating BTC sliders with "Cherry MX mount"