Gemi Elettronica Wire tensioner with cogwheel lock, Electric Fence, Electric Fences Wire tensioner with cogwheel lock; useful for building an electric fence to tension the wire or webbing. Gemi's turnbuckle is made of stainless steel, a robust material that guarantees a long service life on the electric fence. Equipped with toothed wheel locking system, ideal for electric fences for horses, ponies, cows, goats, sheep, boars, deer, cattle, etc.