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HMX FJ400 vs. Durock Sea Glass

An in-depth look at the HMX FJ400 and the Durock Sea Glass switches—which one is the best fit for you?

Overview

When it comes to mechanical keyboard switches, the HMX FJ400 and the Durock Sea Glass offer distinct yet appealing experiences for typists and gamers alike. The FJ400 is celebrated for its balanced sound profile, positioning itself as a solid choice for those seeking an all-around linear switch that provides a satisfying typing experience without distractions. On the other hand, the Durock Sea Glass switches stand out not just visually with their pastel color options, but also for their unique typing feel, thanks to a proprietary material blend that delivers a featherlight touch coupled with a distinctively hollow sound signature. While the FJ400 is ideal for users looking for reliability and consistent performance, the Sea Glass might appeal to those who appreciate a more whimsical aesthetic alongside an exhilarating typing experience. However, let's dive in a bit deeper beyond generalities so you can best decide on the best switch for you.

By the numbers

Technical specifications

Actuation force

50g

Actuation force

45g

Bottom-out force

58g

Bottom-out force

62g

Pre-travel

2.00 mm

Pre-travel

2.00 mm

Total travel

3.80 mm

Total travel

3.80 mm

Factory lubed

Yes

Factory lubed

Yes

Stem construction

Standard

Stem construction

Standard

Stem material

T2

Stem material

P3+

Top housing material

POM

Top housing material

Polymer nylon and UHMWPE blend

Bottom housing material

Nylon

Bottom housing material

Polymer nylon and UHMWPE blend

Mount type

PCB (5-pin)

Mount type

PCB (5-pin)

Spring

22mm single-stage spring

Spring

Gold-plated

Housing materials

The HMX FJ400 and Durock Sea Glass switches utilize different materials for their top and bottom housings, leading to varied acoustic characteristics. The FJ400’s top housing is made from POM, known for producing a deeper and more muted sound profile that creates a unique auditory experience. In contrast, the Sea Glass employs a blend of polymer nylon and UHMWPE for its top housing, which offers a brighter sound profile that is described as pleasant but not sharp. This difference suggests that pressing the switches will result in distinctly different sound signatures at the peak of keypress action, with the FJ400 providing a more subdued tone while the Sea Glass produces a brighter, more vibrant sound.

When examining the bottom housings, both the FJ400 and Sea Glass utilize nylon but with differing formulations. The FJ400’s nylon bottom housing is touted for its ability to deliver a deeper, fuller sound due to the material's softer nature, which absorbs sound waves and diminishes sharpness. On the other hand, the Sea Glass’s blended nylon and UHMWPE bottom housing attempts to create a similar pleasant audio output but leans slightly brighter. As a result, while the FJ400’s bottom housing may contribute to a rounded typing experience, the Sea Glass can still offer an enjoyable feel and auditory experience. Thus, while they both incorporate nylon, the mixed material of the Sea Glass could produce a more nuanced sound depending on key release and bottom-out dynamics.

In summary, though the materials are different for the HMX FJ400 and Durock Sea Glass, the interaction between the top and bottom housings plays a critical role in shaping the overall sound profile experienced during use. The FJ400's specific POM top and nylon bottom combination often result in muted depth, while the Sea Glass's polymer blend allows for a brighter and potentially more dynamic typing experience. Regardless of these differences, users can still achieve a satisfying auditory response by understanding how these varied materials influence sound during both action and release phases. The distinctive sound profiles, though resulting from different compositions, demonstrate how each housing's individual characteristics can be harmoniously combined to create an enjoyable typing experience.

Weight

When comparing the HMX FJ400 linear switch and the Durock Sea Glass linear switch, there are notable differences in their actuation and bottom out forces. The FJ400 has an actuation force of 50 grams and a bottom out force of 58 grams, while the Sea Glass features a lighter actuation force of 45 grams paired with a higher bottom out force of 62 grams. This means that while the Sea Glass requires less force to register a keystroke, it ultimately necessitates more effort to fully depress the key. Consequently, the FJ400 presents a heavier typing experience overall, which may appeal to users who prefer a more substantial feel in their typing. In contrast, the Sea Glass allows for easier actuation, potentially making it more comfortable for prolonged typing sessions, although it does result in a greater push needed to bottom out. Overall, users seeking a lighter switch with less actuation force might lean towards the Sea Glass, while those who prefer the weightier feel will likely gravitate towards the FJ400.

Travel distance

Both the HMX FJ400 linear switch and the Durock Sea Glass linear switch have an identical travel distance of 3.8 mm, which means that the tactile experience of pressing down on either switch will feel quite similar. With both switches traveling the same distance from the top to the bottom, users can expect a comparable keypress feel, making them equally suitable for those who prefer a specific actuation depth. Whether you choose the FJ400 or the Sea Glass, you’ll achieve a consistent and uniform typing experience due to their matching travel distances.

Price comparison

Which switch is more bang for your buck?

The HMX FJ400 has an MSRP of $3.50 per 10 switches. At Milktooth, we are able to pass on savings to our customers and offer the FJ400 for $3.29.

The Durock Sea Glass has an MSRP of $5.80 per 10 switches. At Milktooth, we are able to pass on savings to our customers and offer the Sea Glass for $4.87.

Here at Milktooth, we offer the best prices on switches (on average, 27% lower the competition). In addition, we offer free shipping on orders over $49.00. We also offer free returns and exchanges, so you can shop with guaranteed satisfaction.

That said, while price is an important piece of the puzzle, our opinion is that you should ultimately pick the option that most suits your unique preferences since you’ll be using these switches for years to come. In other words, finding something perfect for you is, in our view, the most important criteria.

Typing experience

The sound profile of the HMX FJ400 linear switch is reported to be well-balanced, making it an ideal choice for users who appreciate a more neutral auditory experience while typing. It is designed to produce a sound that complements the typing experience without being overly intrusive. In contrast, the Durock Sea Glass linear switch has a distinctively hollow sound signature, which lends a unique character to the typing experience. This airy and wisp-like sound is attributed to its proprietary material blend, offering a different acoustic texture during use. While both switches produce sound, users can expect the FJ400 to be more subdued and even, while the Sea Glass delivers an airy tone that contributes to the overall typing ambiance.

When it comes to the feel of these switches, the FJ400 occupies a middle ground, providing a smooth typing experience that caters to a wide range of preferences without leaning too far in any direction. It offers a gentle yet assured actuation that can be very appealing for users who prefer an accessible yet reliable response. Meanwhile, the Durock Sea Glass switches excel in providing a frictionless feel. This effortless actuation coupled with a mild resistance results in a typing experience that feels light, almost feathery, which dramatically reduces finger fatigue over long sessions. The combination of a low actuation force and a smooth travel path of the Sea Glass switch contributes to its reputation as an incredibly comfortable typing option.

In summary, both the HMX FJ400 and Durock Sea Glass linear switches offer distinct experiences, with the FJ400 providing a balanced sound and a smooth feel suitable for general use, while the Sea Glass combines a uniquely hollow sound with an incredibly frictionless and airy typing experience. Your choice between these two will hinge on whether you prioritize a subdued auditory experience with the FJ400 or crave the distinct, light character of the Sea Glass. Regardless of your choice, both switches promise to deliver a satisfactory typing experience, just in different flavors.

Conclusion

To conclude, choosing between the HMX FJ400 linear switch and the Durock Sea Glass linear switch largely depends on your preferences in tactile feedback and sound, as well as your specific typing context. If you are looking for a well-rounded, balanced experience that caters to both casual typing and gaming, the FJ400 is an excellent choice with its medium bottom-out force of 58 grams. Its mild characteristics create a more approachable typing experience that can minimize fatigue during prolonged use. In contrast, if you prioritize a uniquely airy and frictionless feel coupled with a visually appealing design, the Durock Sea Glass is the way to go. With a slightly heavier bottom-out force of 62 grams, it offers a weightless sensation and a distinctive hollow sound profile that stands out from the crowd. Its smooth and feathery typing experience makes it ideal for those who value an effortless touch, whether for extensive creative writing or gaming. Ultimately, your decision should align with your typing style and aesthetic preferences, ensuring that you find the switch that feels most comfortable and satisfying for your needs.

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