Torx keys, also known as Torx wrenches or Torx drivers, are used for tightening or loosening screws and bolts with a specific Torx-shaped head. Torx is a type of screw drive system, designed to provide a higher torque transfer and reduce the risk of slippage compared to other drive types. Torx keys are commonly used in various industries, including automotive, electronics, and machinery, where precise and secure fastening is required. The Ronix RH-2036 long-arm Torx keys are identified by a number that corresponds to the size of the screw. The smaller the number, the smaller the screw; so, It is important to choose the right size wrench for the screw you are using, as a wrench that is too small may slip and one that is too large may damage the screw. There are 9 different sizes in this kit ranging from T10 to T50, so it is important to choose the right size for the job.