The BCI STIRRUP 25 degree Angled Thumb Rest for M-LOK provides a more aggressive angle for added control and accuracy while shooting. Available in 15 degrees and thumb print versions, with textured grip for secure handling. A sturdy base for your thumb, compatible with or without gloves. Choose the Left or Right by the side of the rail you prefer...Lefty pick RIGHT, Righty pick LEFT.  Sorry for the confusion!