This Estella thickness adjustment knob is a direct replacement for the one that came standard on your Estella SL series meat slicer. It is compatible with SLM12, SLM13, SLA13, and SLA13S meat slicers. This knob allows you to adjust the thickness for your meat slices and other foods. If your original thickness adjustment knob is worn out or broken, replace it promptly to continue proper operation of your meat slicer.