This compound lets you select the particle strand's segment size mode for display and rendering, using the particle's ShapeSizeAbsolute attribute as a reference.
For more information, see Rendering the Absolute Size for the Segment and Point Shapes.
Plug its Execute output into the Execute on Emit port of an Emit compound to set this value once, or plug it into an Execute port on the Simulation Root or a port on the ICETree node to update at every frame.