Ensure selected keyframes’ handles have equal length.

Side

Side of the keyframes’ Bézier handles to affect

Left

Equalize selected keyframes’ left handles.

Right

Equalize selected keyframes’ right handles.

Both

Equalize both of a keyframe’s handles.

Handle Length

Length to make selected keyframes’ Bézier handles.

Flatten

Make the values of the selected keyframes’ handles the same as their respective keyframes.