Steel,solid,bueatiful shape,easy to install,used for different machines Quick CouplingNylon 25mm ID,39mm OD1" ID,1-1/2" OD32mm ID,48mm OD1-1/4" ID,1-7/8" OD32mm ID,51mm OD1-1/4" ID,2" OD32mm ID,55mm OD1-1/4" ID,2-5/32" OD Steel 25mm ID,39mm OD1" ID,1-1/2" OD32mm ID,48mm OD1-1/4" ID,1-7/8" OD32mm ID,51mm OD1-1/4" ID,2" OD Aluminium 32mm ID,48mm OD1-1/4" ID,1-7/8" OD Brass 32mm ID,48mm OD1-1/4" ID, ...