Drop outs (derailleur hangers) are a sacrificial component of your bike, designed to bend or break in the event of an accident - saving your frame from being damaged. Always have a spare, as the bike is un-rideable without one. - Cast Aluminum - Suitable for Shimano's direct mount rederailleur system. - Not suitable for thru axles Fits: Bike Model Type Year Cleo 20 24 2013-2014 Strattos S1 2016 Monarch Series 2012-2014 Monarch 4 5