From the manufacturer
The THenar was designed to enhance the operators ability to consistently place their grip in the same location. Additionally, the THenar incorporates a quick detach sling swivel mount, reducing the number of accessories on your rail. Doing more with less, enhancing target engagement time, while increasing weapon control, the THenar will dramatically improve your shooting performance.
THenar picatinny comes with one THenar, Instructions, Bridge and screw. Assembled and installed in seconds.