Pacify 4 Pack Chain Tensioner Set with 2pcs 1-3/4" Roller Spring for Mini Bike Chain Tensioner Bicycle Coleman CT200U BT200X Trail CT200U-EX Powersports BT200XSpecification: Material: iron Size: 11*8*5cm Weight: 200g Feature: * Material -The chain tensioner is made of iron, which is sutrdy. *Purpose: Adjust the tightness of the chain. *Applicable..