It's all about quicker response and firming up the brake pedal! Techna-fit brake lines are made of the finest PTFE hose and permanently crimped-on zinc plated steel fittings and assembled in the USA. Each and every Techna-fit brake line set is pressure tested to 3000psi and is guaranteed leak-proof. The protective outer Stainless steel woven lines shield the innner core that consist of a PTFE (commonly referred to as Teflon®). It is that protected inner core that carries the brake fluid itself and is very resistant to expansion under pressure nor does it degrade from exposure to brake fluid.