Linear strand construction gives shift housing its compressionless behavior. When cable tension pulls against the housing, linear strands resist shortening because they run parallel to the force rather than spiraling around it like brake housing. Jagwire's 4mm Derailleur Housing uses this construction to maintain consistent indexing across the cassette, keeping shifts crisp whether you're clicking through gears on flat roads or grinding up a climb under load.

The 4mm diameter is the current industry standard, fitting the housing stops and barrel adjusters on modern road, mountain, and gravel frames. An internal liner reduces friction as the cable slides through, and the outer jacket shields the structure from water, grit, and cable rub. The housing stays flexible enough to route through tight frame entries without kinking while holding its shape where it matters for clean cable action.

Each roll provides 5 feet of housing, enough for a complete shift system with some left over. Cut to length with a sharp cable cutter and finish each end with a 4mm ferrule for proper seating against stops. This is basic replacement housing that gets the job done without extra cost when you're refreshing cables on a daily rider or finishing a budget build.