Guide
Anti-climb fence: 4 x 2 inch knotted mesh or 358 welded mesh panels?
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An anti-climb fence, such as a 4 x 2 inch knotted mesh or a 358 welded mesh panel, has openings too narrow for a toe or finger hold. SIMO Securon makes the ZS-Knot™ 4 x 2 inch anti-climb knotted fence, supplied in rolls. Compare the two by specification: opening, wire, coating, posts and toppings.
Why is a 4 x 2 inch grid hard to climb?
A climber needs a hold for a toe or the fingers. A 4 x 2 inch grid gives none: its line wires are 4 inches apart and its stays 2 inches apart, so the openings are too narrow to step into or grip. Three more things decide whether the fence can be climbed:
- Height: 6 ft, or 8 ft for higher security.
- A topping that cannot be climbed past: RTHT™ barbed wire and concertina coil on the post attachments, kept continuous across every post so there is no gap.
- No gaps: at the posts, at the gates and along the ground.
In India, the words anti-climb fence often mean 358 welded mesh panels rather than a 4 x 2 inch knotted mesh. Both answer the same need with a narrow opening; they are built differently.
ZS-Knot 4 x 2 or 358 welded mesh: how do the specifications compare?
| ZS-Knot 4 x 2 inch knotted mesh | 358 welded mesh panel | |
|---|---|---|
| Construction | A knotted mesh: a separate knot wire wrapped above and below the line wire at every crossing | A rigid panel: wires welded at every crossing |
| Opening | 4 x 2 inch (101.6 x 50.8 mm) | About 3 x 0.5 inch (76.2 x 12.7 mm) |
| Wire | Top and bottom line wires 3.00 to 3.10 mm; other wires 2.45 mm, 700 to 800 MPa | Usually 4 mm |
| Coating | Zn-Al: Zn-Al 90/10, 240 GSM minimum (Alpha) or Zn-Al 90/10, 120 GSM (Zeta Nova) | As each maker specifies |
| Supplied as | Rolls of 50 m | Panels |
| Fixing | QvikFixrr™ clips at every post; fabric locks and M10 fasteners at strain, terminal and corner posts | Clamp bars and bolts at each post, the panels overlapping the post |
| Heights | 6 ft and 8 ft (24 rows at 8 ft) | Several panel heights |
| Toppings | RTHT barbed wire and concertina coil on the post attachments | As specified |
| Rated life | 35 years or more (Alpha), 20 years (Zeta Nova), in C1 to C3 environments | As each maker states |
The 358 figures come from the published specifications of UK and New Zealand makers, listed under sources; they differ between makers, so check them on the panel you are offered.
Which suits your site?
Choose by what your specification asks for. Where a tender or a security consultant specifies 358 welded mesh panels, that is a panel system, which SIMO Securon does not make. Where the specification asks for an anti-climb mesh by its opening, wire, coating and height, put the ZS-Knot 4 x 2 inch knotted mesh beside it line by line.
The ZS-Knot 4 x 2 is SIMO Securon’s fence for sites where the threat is a person climbing rather than an animal crossing: factories, warehouses, data centres, high-security sites and the people side of solar parks. For those, SIMO Securon suggests the 4 x 2 anti-climb fence in Alpha, up to 8 ft, with RTHT barbed wire and concertina coil. See industrial fencing and the full ZS-Knot 4 x 2 specification. Testing, with NABL-accredited laboratory reports on request, is on quality and testing.
What sets the price of a ZS-Knot 4 x 2 fence?
A 4 x 2 anti-climb fence is priced for its site, along the boundary: by the length, the height, the grade, the posts and foundations, the toppings, the gates and the installation. Send the drawing or the boundary length with your RFQ for a bill of quantities and a price.
FAQ
4 x 2 anti-climb fence questions
What are the specifications of a 4 x 2 anti-climb fence?
SIMO Securon's ZS-Knot 4 x 2 inch anti-climb knotted fence has line wires at 4 inch (101.6 mm) centres and stays at 2 inch (50.8 mm) centres, knotted at every crossing; top and bottom line wires of 3.00 to 3.10 mm and other wires of 2.45 mm, 700 to 800 MPa; Zn-Al coating; up to 8 ft; in 50 m rolls.
ZS-Knot 4 x 2 specificationIs only the 4 x 2 inch grid anti-climb?
Yes. Only the 4 x 2 inch grid is anti-climb: its openings are too narrow for a toe or finger hold. SIMO Securon also makes the ZS-Knot in 4 x 4 inch and 3 x 3 inch grids, which are not anti-climb.
What does a 4 x 2 anti-climb fence for a factory cost?
A 4 x 2 anti-climb fence is priced for the site: by the boundary length, the height, the grade, the posts and foundations, the toppings (RTHT barbed wire, concertina coil), the gates and the installation. Send the drawing or boundary length with your RFQ for a bill of quantities and a price.
What is a 358 fence?
A 358 fence is a rigid welded mesh panel with openings of about 76.2 x 12.7 mm (3 x 0.5 inch), usually of 4 mm wire, fixed to posts with clamp bars and bolts. The name comes from 3 inch by 0.5 inch by 8 gauge. SIMO Securon does not make welded mesh panels.
Sources
- 358 mesh panels: specification (product page) (opens in a new tab), A UK fence maker, read 17 October 2026
- 358 mesh system: wire centres, fixing and post centres (product page) (opens in a new tab), A UK fence supplier, read 17 October 2026
- 358 mesh: where the name comes from (product page) (opens in a new tab), A New Zealand fence maker, read 17 October 2026
Talk to the SIMO Securon team
Call or WhatsApp us with your site type, location and boundary length, and we will come back with a recommendation.