I-Spec is an integrated mounting system for brake and shifting levers. It just needs one bracket which saves space, provides a cleaner optic and saves weight. The adapter allows the shift lever to be attached directly to the brake lever. Especially for the SL-M8000 shift lever in combination with the BL-M8000-I brake lever (I-Spec II - not compatible to other I-Spec systems). Delivering according to your selection of adapter for left or right.