1" Disk with 360 Cycles Per Revolution (CPR)- Available in packs of 10.

US Digital offers a wide variety of standard HubDisk assemblies (optical encoder disk attached to an aluminum hub) to aid mounting onto a shaft. 

Encoder disks may also be ordered as stand-alone items. The rotary encoder disks are made from 0.007 in. thick Mylar polyester film, and the material allows for a -40C to 100C temperature range. 

The disk on the HubDisk assembly comes attached with the emulsion side up when the disk text is right-reading. HUBDISK-1 consists of a precision machined aluminum hub fastened to a 1 in. diameter optical encoder disk (DISK-1 (https://www.usdigital.com/disk-1)). 

One .050 in. flat-to-flat set screw is used to fasten the hub to a shaft. 

All HubDisk assembly bores are held to a very tight tolerance defined by US Digital Technical Bulletin, Shaft and Bore Tolerances TB1001