John Deere®
Tractors with 11" Single with IPTO without Reverser - 300, 301, 301A, 302

Tractors with Flywheel AT29754 - 1020, 1520
Tractors with Flywheel AR66781 - 2440, 2630, 2640

Tractors with 11" Single with IPTO with Flywheel AT29695 - 2020, 2020 Mannheim, 2030, 2030 Mannheim, 2120, 2120 Mannheim

Tractors with 11" Single with Transmission PTO or with out PTO - 301A, 302

Tractors with 9"/11" Dual Cover Assembly Includes PTO Disc with Continuous PTO with Flywheel AR66070 - 2630, 2640

11"
15 Spline - RCO*

*Definition:
RIGID
This term refers specifically to the drive plate that is attached directly to the solid steel plate. Opposite of dampened.
CUSHIONED
The clutch lining/steel plate will have some type of link to absorb the shock load. Most commonly you will see extra rivets and links between the ID of the facings and the OD on the drive plate. Not one solid steel plate.
ORGANIC
Organic clutch material is most commonly used in agricultural clutch discs. It provides the most flexibility.