Mine has stamped on the back(rear 1 3/8 ) (front 3/4) it has 3 angled slots for attachment and adjustment
The left roller has 2 pennies offset the other has 7 pennies offset. The rollers are 3/4" nylon. If there is a better material offered I would prefer that upgrade. If I can be of anymore assistance please ask.
The 2pennies are 1/8" 7 pennies is 3/8" sorry I didn't have a tape measure at the time. Thank you for your help on this matter.
Kurt