High tensile (H-T or HT) fencing is a special hard, springy steel wire that was introduced in the 1970s and has slowly gained acceptance. The wire may be a single strand plain or barbed wire, or woven mesh, and is capable of much higher tension than mild steel. It permits the use of wider post spacings and is neither stretched easily by animals, nor by fallen trees or branches. It can be insulated and electrified. Because of the wide spacing of the posts, thin metal or wood spacers (or "droppers") may be attached to the wires between posts to maintain their spacing.
Joining HT wire is difficult because of its stiffness and its reduction in strength when bent sharply. However, it may be joined effectively with proprietary clips. HT wire is more expensive than mild steel, but because of the need for fewer posts, the overall cost of the fencing is usually comparable.
Because it does not stretch, animals are less likely to become entangled in HT wire. However, for the same reason, if an animal does become entangled or runs into a few strands at a high speed, it can be deadly, and is sometimes referred to as having a "cheese slicer" effect on the animal.
Trellising for horticultural purposes is generally constructed from HT wire as it is able to withstand a higher crop load without breaking or stretching.