Ratchet Wire Strainers are a specialist product for straining fencing line wire and barbed wire.
To strain the wire: attach the base of the strainer to a post using the fixing hole, feed your wire through the hole in the barrel of the strainer and then wind the barrel with a spanner. When the wire reaches your required tension, engage the ratchet catch to secure the wire in place. The wire can easily be re-tensioned when required.