Monofilament wire, also known as tension wire, is used on a lot of different fence types to strengthen fences at the top and to keep the mesh tight from post to post. Having fence tensioning eliminates sagging between posts, if they are spaced 10 feet apart or closer.
The reason why fence tensioning wire is necessary is because if sagging between posts is present, then wildlife such as deer and coyotes can easily jump into the yard. Having tension wire at the top will keep the fence mesh taut to block jumping attempts by wild animals that may try to harm puppies and kittens.
Fence tensioning is also useful for areas with high winds and trees. Remember, if a tree branch falls on a fence, it may damage the system; but with tensioning, it will keep the fence strong.
When installers consider tensioning fence, think about strength and security.