Switch Housing Materials: Polycarbonate, Nylon, and POM

Why switch housing material matters

The housing of a mechanical switch is the plastic shell that holds the stem, spring, and contacts. It is typically made of two parts: the top housing and the bottom housing. The material of these parts affects how the switch sounds when the stem bottoms out and returns, and it also influences the friction your fingers feel while typing.

Unless you are deeply familiar with switch design, you often do not think about housing plastic, but it is one of the largest variables in a switch's character. The same stem and spring can sound noticeably different when placed in a polycarbonate top versus a nylon top. When you are choosing a keyboard or a set of switches for a hot-swappable board, understanding these materials helps you predict the result without hearing it first.

If you are new to switches, start with our guide to mechanical switch types to see how the whole mechanism works. Then come back here to focus on the housing.

Polycarbonate (PC) housings

Polycarbonate is a transparent or translucent plastic that is stiff and durable. It is often used for switch tops that need to allow light from RGB LEDs to shine through. Many clear switches, such as the common "clear top" designs, use PC for the top housing.

In terms of sound, PC tends to produce a crisper, higher-pitched clack than softer plastics. It does not absorb as much vibration, so the impact of the stem on the housing is transmitted more directly. This can make a keyboard feel more responsive and sound more defined, though some find it sharp on the ears.

If you want a bright, clean sound with good RGB lighting, a switch with a PC top is a safe choice. Because PC is hard and smooth, it also slides well against the stem, so it often feels a bit more polished than nylon, though not as slick as POM.

Nylon housings

Nylon is a softer, more flexible plastic that is commonly used for switch bottoms. It has a matte finish and is usually opaque, which means it blocks most light. Switches that use nylon for the bottom housing are sometimes advertised as having a "nylon bottom" or "PA66" or "PA12" in the spec sheet.

The acoustic character of nylon is the opposite of polycarbonate in many ways. Nylon absorbs more high-frequency energy, so the bottom-out sound is deeper and more muted. Enthusiasts often describe nylon housings as producing a "thock" rather than a "clack." The sound is softer and less resonant, which can be welcome in an office or shared space.

Nylon also has a slightly higher coefficient of friction than POM, but it can be polished or lubricated. In practice, a nylon bottom with a well-lubricated stem feels smooth and stable. If you prefer a deeper, quieter typing sound, switches with nylon bottoms are worth considering. For a broad look at how sound and noise are handled, see our article on keyboard noise levels.

POM (acetal) housings

POM, also known as acetal or polyoxymethylene, is a tough, low-friction engineering plastic. It is often used for switch stems because of its self-lubricating properties, but full POM housings also exist, or a switch may have a POM bottom and a PC top.

POM is known for being exceptionally smooth. The material naturally repels friction, so a POM stem sliding inside a POM housing can feel almost buttery, even without lubrication. This is why many premium switches use POM for both parts, or POM for the stem and nylon for the bottom.

In terms of sound, POM tends to be a middle ground. It is harder than nylon, so it does not mute as much, but it is not as resonant as PC. The result is often a pleasing, balanced clack with a slightly tactile nuance. POM is also highly durable and resists wear, which contributes to a consistent feel over years of use.

If you want a switch that feels smooth and sounds neither too sharp nor too dull, a POM design is a strong option. Many linear switches that focus on a smooth glide use POM stems and PC top housings. For more on the feel of different switch types, see our comparison of linear vs tactile vs clicky switches.

How to identify housing materials from specs

Switch manufacturers usually list the housing material on the product spec sheet or on the packaging. Look for abbreviations like "PC" for polycarbonate, "PA" for nylon (often with a number like PA66 or PA12), and "POM" for acetal. Some sheets will say "top housing: PC, bottom housing: nylon" or "all POM housing."

If the material is not listed, you can make a guess based on appearance. Clear or translucent housings are almost always polycarbonate because nylon and POM are typically opaque. If the housing is milky white or a solid color, it may be nylon or POM. But some manufacturers use a clear nylon or a mix, so this is not a rule, just a hint.

Another approach is to check the switch's sound and feel by listening to a sample or reading descriptions. Many vendors provide sound tests, but remember that YouTube videos compress audio and your keyboard case also changes the sound. For a more scientific mindset, see our article on keyboard case materials because the case also plays a big role.

When in doubt, look for a switch that explicitly states its housing composition. This is common on premium switches, and it is a sign the manufacturer expects you to care. If you are building a keyboard, you can also buy a small sample set to test before committing to a full board.

How to choose the right housing for your build

There is no single best housing material, only what fits your taste. If you are building your first mechanical keyboard, consider what sound profile you want. Do you prefer a sharp, defining clack? That points to PC. Do you want a deep, muffled thock that is office-friendly? Nylon is the classic choice. Do you want a balanced feel with low friction? POM is worth a try.

Also think about the other components. Keycaps, plate material, and the case itself all interact with the switch housing. For example, a PC switch on an aluminum plate will sound very different from a nylon switch on a polycarbonate plate. Our guide to keyboard mount styles explains how the case and plate affect sound.

For most people, the differences are subtle on a prebuilt keyboard because the board's case and keycaps dominate the sound. But if you are building a custom board or buying a hot-swappable keyboard, the switch housing is one of the few variables you can control. That makes it worth paying attention to.

If you want a quick way to compare many keyboards with different switches, browse our best mechanical keyboards guide. For a hot-swappable board that lets you try different switches later, see our best hot-swappable keyboards list.

What to pick for your use

Questions

Does the housing material affect the sound more than the keycap?

Both matter, but in different ways. The keycap is the surface your finger hits and it can dampen or amplify the sound, while the housing is the chamber that resonates. On a prebuilt keyboard, the keycap often dominates, but on a custom build where you choose both, the housing becomes a primary tone control.

Can I mix housing materials within one switch?

Yes, many switches use a PC top and a nylon bottom, or a POM stem with a nylon bottom. This is common to balance lighting, smoothness, and sound. The spec sheet will usually tell you which material is used for each part.

Are all clear switch housings polycarbonate?

Almost always. Polycarbonate is the standard choice for clear housings because it is transparent, stiff, and resistant to scratching. However, some manufacturers use a clear modified nylon, so it is not a 100% guarantee. Always check the spec sheet if the material is important to you.

How do I know what materials are used in a switch that I already have?

Look up the switch model online. Manufacturers often publish detailed spec sheets. If the switch is generic, you can sometimes identify polycarbonate by its crystal-clear appearance, but nylon and POM can look similar. In that case, rely on sound: a bright, hollow sound suggests PC, while a duller sound suggests nylon.