You can only truly judge a seat harness after a two-hour session, not from a quick try-on in the shop. The ION Sonar 2025 is ION's lightest hard-shell harness, and unlike its counterparts, it includes a lumbar pad. ION designed this harness for fast kitefoiling, where the traction never really lets up. It's available in five sizes, from 46 to 54, and comes in black.
KEY INFORMATION
ION Sonar 2025, kitefoil seat harness with hybrid shell and lumbar pad
What we like
- Hybrid shell: partially molded Curv composite material, firm back, flexible sides
- Lightest hard-shell harness in the ION range: lightweight structure and material mix
- Spectre Bar 2: the latest generation of ION spreader bar, with a thin and flexible profile
- Lumbar pad: unique to the Sonar, supporting the lower back
- Adjustable strap: positioned between the leg straps and the buckle, keeping the hook low
- Integrated Kiteknife, C_30 buckle, HD foam, and neoprene belt
Available sizes
Use
Recommended level
Included / Not included
- ✅ Included: harness, spreader bar with hook, kite knife, safety leash handle
- ❌ Not included: nothing, the harness comes complete
DETAILED DESCRIPTION
A hard shell that stays flexible where it counts
The Sonar features the same hybrid construction as the Radar: a Curv composite shell molded for the back, paired with flexible sides. This design ensures the back stays supported while the sides move with your body. This combination provides firm hold without turning the harness into a corset, even with constant traction throughout your session.
Weight: ION's primary argument for this model
ION positions the Sonar as the lightest and most durable hard-shell harness in their catalog. This is due to its lightened structure and revised material assembly. When foiling, you're hooked in for extended periods, and your body works backward. While every gram feels less significant than on a twin-tip, bulk is immediately noticeable.
Lumbar cushion: the real difference from the Radar
The Sonar includes a lumbar cushion, a feature not found in the rest of the range. It fills the hollow of your lower back, distributing pressure instead of concentrating it on the shell's edge. This significantly improves comfort during long foiling runs, especially when the load is continuous and your position remains relatively static.
Spectre Bar 2 and low hook position
The Spectre Bar 2 is ION's latest spreader bar, featuring a thin profile, high flexibility, and a C_30 buckle. An adjustable strap connects the leg straps to the harness buckle, keeping the hook in a low position and preventing it from riding up towards your chest. The Kiteknife is integrated into the harness, along with HD foam and a neoprene belt for comfortable wear.
SIZE GUIDE AND TECHNICAL SPECIFICATIONS
ION harnesses are sized from 46 to 54, which translates to XS, S, M, L, and XL. To find your perfect fit, measure your waist at its narrowest point, just above your navel. If you're between sizes, swing by our Pornichet store to try them on, or simply give us a call.
| Size | Waist size (cm) |
|---|---|
| XS (46) | 66 to 76 |
| S (48) | 74 to 84 |
| M (50) | 82 to 92 |
| L (52) | 90 to 100 |
| XL (54) | 98 to 108 |
Official ION chart, Harness Waist Men table, ion-products.com, recorded on 08/28/2026.
| Specifications | |
|---|---|
| Product | ION Sonar 2025 |
| Type | Kitesurf and kitefoil seat harness |
| Construction | Hybrid shell, with a partially molded Curv composite. |
| Spreader bar | Spectre Bar 2 with hook |
| Buckle | C_30 |
| Padding | HD foam and lumbar pad |
| Belt | Neoprene |
| Safety | Integrated multi-function Kiteknife |
| Hook hold | Adjustable strap connected to the leg straps |
| Available sizes | 46 (XS) • 48 (S) • 50 (M) • 52 (L) • 54 (XL) |
| Color | 900 black |
| Delivered with | Spreader bar with hook, kite knife, safety leash handle |
| Level | Advanced to expert |
| Year | 2025 |
FAQ
Sonar or Radar: which one to choose for foil?
Both share the hybrid shell and the Spectre Bar 2. The Sonar goes further in two ways: it is lighter, and it has a lumbar pad that the Radar does not. For high-speed foil sessions, choose the Sonar. For a mixed twin-tip and foil riding style, the Radar does the job.
What is the Spectre Bar 2?
It is ION's latest spreader bar, fitted as standard on the Sonar 2025. It has a slim profile, high flexibility, and a C_30 loop. It distributes the load across the entire width of the harness instead of concentrating it on the hook. The kite hook is included.
Why a seat harness rather than a waist harness for foil?
It won't ride up. The leg straps lock the harness to your pelvis, keeping the pull point low. When you're foiling, with continuous pull and your body leaning back, this design prevents the bar from ending up under your ribs by the end of your session.
What size ION Sonar should you choose?
Sizes range from 46 (XS) to 54 (XL) and are based on your hip circumference. If you're between two sizes, trying it on is the safest option. We have the models in our Pornichet store, and we're available by phone to help.
What comes with the harness?
The Sonar comes complete: a spreader bar with its hook, a kite knife, and a safety leash handle. You won't need anything else before your first session.
Why buy from GlissEvolution?
Why buy from GlissEvolution? We bring over 20 years of expertise in watersports. Our passionate advisors rigorously test gear on the legendary spots of La Baule and Pornichet. We offer responsive after-sales support right here in France, a 2-year warranty, free shipping on orders over €150, and the convenience of in-store pickup in Pornichet.
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