Sunlite SIS Housing Boxes

SIS stands for Shimano Index System. These housings are specifically designed with a longitudinal wire structure that prevents compression, which is essential for the precise cable movement required by indexed shifting systems.

These are strictly for shift cables. Using them for brake systems would be dangerous because brake housings are constructed differently to handle the high-pressure compression forces of stopping, whereas these are optimized for the low-friction, non-compressible needs of gear indexing.

While these are high-quality housings, they are typically sold for shop maintenance and repair tasks. If you are replacing a full-length housing run, ensure the total length you need matches the specific requirements of your bike's frame routing.

Buying in bulk is the standard approach for home mechanics who perform regular maintenance or own multiple bikes. It allows you to cut custom lengths for specific cable runs, reducing waste and ensuring a cleaner, more precise fit compared to generic pre-cut options.