Fourth Element Arctic X: The Cold-Water Undersuit System Built for Serious Divers
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Time to read 8 min
In this blog
-> What Is the Fourth Element Arctic X Range? -> The Full Arctic X Range -> The Technology Behind the Arctic X -> One Piece vs Jacket + Leggings — Which Is Right for You? -> Men's vs Women's — Is It Just the Sizing? -> Building Your Arctic X Layering System -> Built With the Ocean in Mind -> Caring for Your Arctic X Kit -> You may also like...
Fourth Element has quietly become one of the most trusted names in thermal protection for divers — and their latest release makes a strong case for why. The Fourth Element Arctic X range is a complete cold-water undersuit system: jacket, leggings, one piece and socks, all built around the same high-performance fabric technology and designed to work together as a cohesive layering system.
Whether you're diving the British coastline year-round, heading somewhere properly cold, or just tired of being cold on your drysuit dives — this is a range worth paying attention to. We've been stocking Fourth Element for years and we know their kit well, so when we say the Arctic X is genuinely impressive, that's not just marketing talk.
What Is the Fourth Element Arctic X Range?
The Arctic X is Fourth Element's new premium thermal undersuit collection, designed specifically for drysuit divers who dive in cold to very cold water. It replaces the need to piece together a layering system from mismatched kit — every item in the range is built around the same three-layer fabric construction, the same DWR water-repellent technology, and the same philosophy: maximum warmth, minimum bulk.
Every piece is made from recycled materials, certified to Global Recycled Standard (GRS), Oeko-Tex 100 and Bluesign standards, and supplied in plastic-free packaging. That matters — not just as a box-ticking exercise, but because the ocean is the reason we dive in the first place.
The Full Fourth Element Arctic X Range
- Arctic X Men's Jacket
- Arctic X Women's Jacket
- Arctic X Men's Leggings
- Arctic X Women's Leggings
- Arctic X Men's One Piece
- Arctic X Women's One Piece
- Arctic X Socks
The Technology Behind the Arctic X
Three-Layer Fabric Construction
The fabric system that runs through the entire Fourth Element Arctic X range is what makes it stand apart from a standard fleece undersuit. Each garment uses a three-layer construction engineered to trap warmth, move freely, and resist moisture — without adding unnecessary bulk under your drysuit.
Arctic X Fabric Breakdown
| Layer | Composition | Purpose |
|---|---|---|
| Outer Shell | 85% nylon, 15% elastane | Durable, stretchy outer layer with DWR water-repellent coating |
| Inner Shell | 95% polyester, 5% elastane | Mid-layer structure and insulation |
| Lining | 81% recycled polyester, 12% elastane, 7% polyester | Soft fleece layer against the skin — traps warmth, wicks moisture |
💡 DWR Care Tip: Avoid fabric softener when washing — it degrades the DWR coating over time. If water stops beading on the outer shell, a DWR re-treatment spray will restore performance.
4-Way Stretch and Horizontal Trim
This is a detail that separates kit designed by divers from kit designed by people who've never worn a BCD. When you're in horizontal trim — which is where you want to be for most of your dive — garments that aren't cut for this position pull, ride up, and restrict movement in ways that quickly become annoying.
The Fourth Element Arctic X range is specifically engineered for horizontal trim. Articulated sleeves on the jackets and one pieces, articulated knees on the leggings and one pieces, and genuine 4-way stretch throughout mean the kit sits correctly when you're actually diving — not just when you're standing on the boat.
🌡️ Built for cold water — three-layer fabric construction with DWR outer, insulating mid-layer and soft fleece lining
🤿 Designed for drysuit diving — low bulk, 4-way stretch, articulated sleeves and knees optimised for horizontal trim
🧥 Two system options — jacket and leggings for flexibility, one piece for seamless cold-water coverage
♀️ Proper women's cuts — not just resized men's kit, shaped specifically for the female form
🔄 Sustainably made — recycled materials, GRS, Oeko-Tex 100 and Bluesign certified, plastic-free packaging
One Piece vs Jacket + Leggings — Which Is Right for You?
This is the question we get asked most often when it comes to undersuit systems. There's no single right answer — it comes down to how and where you dive.
| 🤿 One Piece | 🧥👖 Jacket + Leggings | |
|---|---|---|
| Thermal continuity | ✅ Seamless — no waist gap | ⚠️ Gap possible at waist on longer dives |
| Versatility | ⚠️ One configuration | ✅ Mix and match layers for conditions |
| Getting dressed | ✅ One garment | ⚠️ Two garments to manage |
| Toilet breaks | ⚠️ More involved between dives | ✅ Easier to manage on the surface |
| Pee valve compatible | ✅ Pee-valve ready | ❌ N/A |
| Best for | Cold water, technical & longer dives | Variable conditions, recreational diving |
| Ideal water temp | Below 12°C | 12°C and above |
Many serious cold-water divers own both — separates for milder days and the one piece when it gets properly cold. Not sure which suits your diving? Our video consultation team can talk it through with you.
Men's vs Women's — Is It Just the Sizing?
No. The jackets and one pieces are genuinely cut differently — not just resized. The women's versions are shaped for the female form with a different cut across the shoulders, chest and hips. For drysuit divers especially, a well-fitting undersuit makes a real difference to both comfort and thermal performance. Always go for the women's cut rather than sizing down in the men's.
Building Your Fourth Element Arctic X Layering System
The Fourth Element Arctic X range works best as a complete system. Here's how to build yours based on the water temperatures you dive in:
🌡️ Cool to Mild Cold Water (12°C – 18°C)
Fourth Element Arctic X Jacket + Leggings as your undersuit layer provides solid thermal protection without over-insulating on milder days. Add the Fourth Element Arctic X Socks to complete the system.
🌡️ Cold Water (7°C – 12°C)
The Fourth Element Arctic X One Piece is the stronger choice here — seamless coverage with no waist gap. Add the Fourth Element Arctic X Socks, and consider a thin thermal base layer underneath for extended dives.
🌡️ Very Cold Water (Below 7°C)
Fourth Element Arctic X One Piece as your primary layer, with a quality thermal base layer underneath — Fourth Element's Xerotherm range pairs well here. Fourth Element Arctic X Socks are essential, and make sure your drysuit is rated for the conditions too.
Built With the Ocean in Mind
Fourth Element's Ocean Positive ethos runs through everything they make, and the Arctic X range is no different. Every garment is made from recycled materials, holds Global Recycled Standard (GRS) certification, and is supplied in plastic-free packaging.
The fabrics also carry Oeko-Tex 100 and Bluesign certifications — independently verified as safe for skin contact and produced to strict environmental and social standards. For divers who've chosen to invest in the ocean through the sport they love, it matters that the kit they wear reflects the same values.
Caring for Your Fourth Element Arctic X Kit
The entire range is machine washable — here's what you need to know to keep it performing at its best:
- 🚫 No fabric softener — degrades the DWR water-repellent coating
- ✅ Machine wash on a gentle cycle at the temperature on the care label
- 💧 Restore DWR with a wash-in or spray-on DWR re-treatment product if water stops beading
- 🧦 Separate sock liners before washing and drying to speed up the process
- 💨 Air dry where possible — extends garment life and preserves the DWR coating
What is the Fourth Element Arctic X range?
The Arctic X is Fourth Element's premium cold-water thermal undersuit system, designed specifically for drysuit divers. The range includes a men's and women's jacket, men's and women's leggings, men's and women's one piece, and socks — all built around the same three-layer fabric construction and designed to work together as a complete layering system.
What water temperatures is the Fourth Element Arctic X suitable for?
The Arctic X range is designed for cold to very cold water diving. As a general guide: the jacket and leggings combination works well from around 12°C upwards; the one piece is the stronger choice below 12°C where seamless coverage and no waist gap matters more; and for very cold water below 7°C, most divers will want to add a thermal base layer underneath as well. That said, how warm you run is personal — if in doubt, our team is happy to talk it through.
Should I go for the one piece or separate jacket and leggings?
It depends on how and where you dive. The one piece gives you seamless, gap-free coverage from neck to ankle — ideal for colder water, longer dives, or technical diving where any weak point in your thermal layering will eventually make itself known. Separate jacket and leggings give you more flexibility to adjust your layering for different conditions and are easier to manage on the surface between dives. Many serious cold-water divers own both. If you're not sure, book a video consultation and we'll help you work it out.
Can I wear the Fourth Element Arctic X under any drysuit?
Yes. The low-bulk construction and slim ankle profile are specifically designed to fit under standard drysuit boots without adding excess volume. The 4-way stretch fabric also helps everything sit smoothly without bunching, regardless of your drysuit brand or style.
Are the Fourth Element Arctic X products pee-valve compatible?
The Arctic X One Piece (both men's and women's) is pee-valve ready, meaning it's designed and constructed to accept a pee valve, but one is not included or fitted as standard. The jackets and leggings are not pee-valve compatible. Fitting is typically carried out by a drysuit technician.
What does "optimised for horizontal trim" mean?
Horizontal trim is the position most divers aim for underwater — body roughly parallel to the seabed. Garments that aren't cut for this position tend to pull, ride up or restrict movement when you're in trim. The Arctic X range features articulated sleeves and knees, along with 4-way stretch fabric, specifically engineered to fit and move correctly when you're in a horizontal diving position rather than standing upright.
Got questions about the Fourth Element Arctic X range or anything else dive-related? We're always happy to talk kit. Drop us an email at support@mikesdivestore.com, book a video consultation with one of our experienced team, or come and see us in person at our Chiswick store — where you'll find expert, face-to-face advice from people who actually dive.
