Zero Tolerance 0230 Jens Anso review: a superior knife from an esteemed maker

The minimalist, ultra-modern Zero Tolerance 0230 Jens Anso slipjoint knife is incredibly light but has serious cutting power – the perfect everyday carry-outdoor knife for a dedicated ultralighter with a taste for premium gear

Zero Tolerance 0230 Jens Anso
(Image: © Matthew Jones)

Advnture Verdict

A top-tier knife with unsurpassed build quality and a price tag to match, the Zero Tolerance 0230 Jens Anso ticks all the boxes for serious knife snobs: an esteemed maker, premium materials including carbon fiber scales and a blade made from one of the most coveted ‘super steels’ out there.


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    Premium build quality

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    Superb 20CV steel blade

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    Incredibly light

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    Minimalist, understated design

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    Blade half stop


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First impressions

The sleek, minimalist and ultra-modern Zero Tolerance 0230 Jens Anso slipjoint knife is immediately eye-catching. It’s a collaboration between cult US brand Zero Tolerance and Danish knifemaker Jens Ansø, a highly regarded designer whose work is increasingly collectable. The 0230 is ZT’s first slipjoint knife, and it really is something special. This is a true ‘knife nut’s knife’, and it has clearly been designed to appeal to the discerning enthusiast – or at least, the sort of person willing to drop the best part of 200 quid or 250 bucks on a pocket-knife.

There’s no denying it has serious pocket appeal, though. The most noticeable feature is its weight – or lack of. This thing is incredibly light, thanks to the use of carbon fiber scales, so it is virtually unnoticeable in a pocket. It’s also very handsome. That metallic grey carbon fiber sheen is enhanced by black oxide steel hardware and a stonewashed blade finish, with a blue ,anodised aluminium backspacer to add a pop of colour.

The spacer also has a cut-out to enable you to add a lanyard – always a nice touch on an everyday carry/outdoor knife, as far as we’re concerned. A good-sized nail nick on the left-hand side of the blade enables you to pull it out, though the fact that plenty of the blade is exposed even when folded ensures it is easy to pinch it open anyway.

The 0230 is just as pleasing to the eye when unfolded as it is when closed. The Wharncliffe blade mirrors the rounded butt of the handle, creating a pleasing symmetry. It is extremely well balanced and sits comfortably in the hand. The action is crisp and the double detent makes an audible click whether fully closed, fully open or at the half-stop. That’s down to the slick internals, which consist of two steel detent balls, one positioned on each side of the blade.

The blade itself is marked with a serial number, place of manufacture (USA), the maker’s name (Anso) and the steel designation (CPM 20CV). Unusually, however, there’s no brand name or logo; instead, you’ll find ‘ZERO TOLERANCE’ stamped along the blade spine, just at the pivot.


• RRP: $245 (US) / £179 (UK)
• Weight: 55g / 2oz
• Blade length: 6.8cm / 2.67in
• Overall length: 15.8cm / 6.22in
• Closed length: 9.3cm / 3.66in
• Materials: CPM 20CV stainless steel blade and carbon fiber scales
• Features: Full flat grind; Wharncliffe blade

In the field

The Zero Tolerance 0230 Jens Anso’s blade is a 2.6 inch (6.8cm) Wharncliffe blade with a full-width flat grind. It’s probably the only traditional element of this knife, but makes for long, precise, and controlled cutting, with little risk of stabbing or piercing anything via the downturned tip. It is ideal for all sorts of outdoor utility work.

The knife’s capabilities are hugely enhanced by the choice of steel: CPM 20CV, a much-coveted ‘super steel’ with exceptional wear and corrosion resistance, not to mention excellent edge-holding ability. For the sake of comparison, 20CV has five times the wear resistance of 440C knife steel, while being slightly harder and with similar toughness. It is also 30% more resistant to corrosion than 440C and has a cutting-edge retention score of 180 on the CATRA test, compared to 440C’s rating of 100. The numbers don’t lie, but real-world performance is even more impressive: it’s truly a pleasure to use, keeping a sharp edge even after putting it through some hard work.

The  Zero Tolerance 0230 Jens Anso is an exceptional pocket-knife with some gorgeous details. As an everyday carry piece it might be out of the reach of many, but will appeal to enthusiasts. We can also see dedicated ultralight backpackers with a taste for premium gear being drawn to the ZT 0230: if you own a DCF (cuben fiber) tent, this would almost be the perfect pocket-knife to complement it.

Matthew Jones

An outdoors writer and editor, Matt Jones has been testing kit in the field for nearly a decade. Having worked for both the Ramblers and the Scouts, he knows one or two things about walking and camping, and loves all things adventure, particularly long-distance backpacking, wild camping and climbing mountains – especially in Wales. He’s based in Snowdonia and last year thru-hiked the Cambrian Way, which runs for 298 miles from Cardiff to Conwy, with a total ascent of 73,700 feet – that’s nearly 2½ times the height of Everest. Follow Matt on Instagram and Twitter.