The SLS Expander is for use with twist-lock Leki Poles. The Super Lock System is used in all Leki twist-lock model trekking poles. The twist-lock design can become loose over time with repeated use. Should you feel your pole is not delivering secure hold it could be the SLS Expander (also called a Leki Split Dowel) needs replacing.
SLS expanders come in 3 colour coded sizes each designed to fit the diameter of the shaft section they need to grip against. Simply match the colour to your existing Expander.