THIS IS A SCHWINN VINTAGE AUTHENTIC ITEM ITS 6 1/4 INCH LONG PART NUMBER 20 585,,,ITS A LONG METAL SPRING TYPE ITEM,,,NOT CERTAIN WHAT ITS FOR ? BUT I THINK YOU MAY NEED ONE OF THEM,lol I WAS JUST TOLD ITS A FLEXABLE HPUSING GOES BETWEEN REAR DERAILUER FERRULE & CHAIN STAY,,,, FOUND IN A SCHWINN SHOP IN NEVER USED CONDITION. FHS