Hit Air bungee cord connects your vest to the grab strap. Your vest won’t work without this cord. Hit air cords are mostly replaced due to loss but, if you have 2 horses running back to back at an event you might find it easier to have a cord on each saddle. The cord is simply nylon with a bungee inside. There is a bit of stretch to the hit air cord due to the bungee. The buckle end of the cord is specific to the type of vest you’re using