Specification: Outside diameter:D19 L25 Outside diameter:D=19mm Height:L=25mm Conversions:1 mm= 0.039inch, 1 inch=25.4 mm The size you can choose: 5X6mm 6X6.35mm 8X8mm 6X8mm 3X8mm 5X6.35mm 8X6.35mm 6.35X6.35mm Conversions:1 mm= 0.039inch, 1 inch=25.4 mm Character: The structure is simple,easy to install,buffer,damping,convenient to disconnect The size is complete and the surface is smooth Connect servo motor,stepper motor,encoder,screw driving,machine,etc Notice: The size is refer to the hole,for example 6X8 is known as one head of the hole diameter is 6mm,the other is 8mm