Hello Everyone

can some one explain a bit about the "Lens Ring Plate for Lens Ring Clamp R1 R10"

what are these

LRP35 (35mm long)
LRP40 (40mm long)
LRP45 (45mm long)
LRP45x (45mm long with protruded end)
LRP50 (50mm long)

and what do they use for ? is this allow me to go -15 on the R1 ultimate ?