Leader lines are typically used as a more durable way to connect air line to the front bags within the wheel well. These black, 20" leader lines are a direct replacement for those found in the Super Low suspension kits and feature 1/8" NPT threading on the bag side and 1/4" NPT threading on the other.
They do not come with any PTC fittings so you may need to pick up a Silver Street Elbow to mate to your bag or an SMC DOT Female Straights to mate the leader line with your existing nylon air line.