This is a replacement master cylinder for a model 60 drum brake surge coupler manufactured by Titan / Dico.  Fits all Titan / Dico model 60 surge brake couplers.  This master cylinder is designed to work with drum brakes.  Its an easy bolt on installation for replacing your old worn out / blown seals master cylinder.  Comes with everything pictured: the master cylinder, boot, lid, gasket, bolts, and cap.  Titan part number 4395100