What is the difference between the Eagle 70 and 90 Transmission derailleurs?

The Eagle 90 Transmission derailleur uses the Type 4 damper as found on GX, XO, and XX Transmission derailleurs. The Eagle 70 Transmission uses a new drag spring damper, featuring higher damper output torque than previous generations of drag spring damper. Different materials also make up the inner cage and inner link, creating a weight difference between the two derailleurs, and each features differences in reparability.