The tension wrench, often called a torque wrench, is used to apply torque to the plug of a lock; in order to hold any picked pins in place. Once all pins are picked, the tension wrench is then used to turn the plug and open the lock. It is typically shaped like a letter "L", although the vertical part of the letter is elongated in comparison to the horizontal part.
Some tension wrenches, called feather touch wrenches, are coiled into a spring at the bend in the "L"; which helps the user apply constant torque. Some users; however, maintain that such wrenches reduce torque control and the feedback available to the user.
Other tension tools, especially those for use with cars resemble a pair of tweezers and allow the user to apply torque to both the top and the bottom of the lock. These would commonly be used with double sided wafer locks.
Also, high tech tension tools exist which sit over the lock face allowing the user to see a display of the amount of torque applied. This aids with the process of feeling when a pin has set since the tension level will drop suddenly then spike again as the next pin sets.
The tension tool is just as important as other tools in the set, but is often neglected and is rarely represented in fiction. It is not possible to pick a pin/tumbler or wafer lock without a tension tool, even with the use of a pick gun.
Famous quotes containing the words wrench and/or tension:
“That is what we must make people feel... the catch in the throat, the wrench to steady the nerves, the determination to carry on.”
—John Dos Passos (18961970)
“The tension to mother the right way can leave a peculiar silence within mother daughter relationshipsthe silence of a mothers own truth and experience. Within this silence, a daughters authentic voice can also fall silent. This is the silence of perfection. This silence of perfection prevents mothers from listening and learning from their daughters.”
—Elizabeth Debold (20th century)