Conveyor Concave Head Roller Small Bearing 3/4 1/4 5/8

Conveyor Concave Head Roller Small Bearing 3/4 1/4 5/8

please help, unidentified bearing. if you know more info about it, please help me out.

this auction is for lot of 1 bearing as shown on the pictures. I don't know bearings much. I know that they are for conveyor, but I am not sure what more info I need to know about them. it has one side flat, and the other side concaved. please take a close look at the pictures to make sure it is what you need. it measures:

OD = about 3/4

ID = about 1/4

thickness = about 5/8

If you know more info about them, please help me out and let me know what they are for and any other info that may help for customers who might be interested.