The Aeroquip Braided Stainless A/C Hose System provides a unique high-tech appearance under the hood. The hose consists of a nylon liner with a braided stainless outer cover. Fittings are 3-piece which include the fitting body, nut and brass olive. Brass olives for use with the Aeroquip Braided Stainless Hose System include an internal O-ring which makes them different from typical brass olives used with PTFE hose. Each fitting comes with a brass olive but it doesn't hurt to have extras when you begin installation. We don't recommend this system for inexperienced installers. If you are skilled at assembling 3-piece fittings, this system works well but it can be challenging if you are new to 3-piece fittings.