Comparison : Item # 11504, 5/16 Inch (in) Actual Outside Diameter (OD) Coupling with Roll Stop
Item # 11505, 1/8 Inch (in) Nominal Inside Diameter (ID) Coupling with Roll Stop
Item # 11506, 1/4 Inch (in) Nominal Inside Diameter (ID) Coupling with Roll Stop
Item # 11507, 3/8 Inch (in) Nominal Inside Diameter (ID) Coupling with Roll Stop
Item # 11508, 1/2 Inch (in) Nominal Inside Diameter (ID) Coupling with Roll Stop