RCBS full length sizer dies can be purchased individually. Many reloaders use an individual full length die if they are neck sizing most of the time, or if they are seating bullets with hand dies. RCBS full length dies have vents to prevent case damage from trapped air or excessive lube.
Big Book Catalog, Issue:66, Page:514
Sinclair, Issue:4A, Page:055
Sinclair, Issue:4A, Page:056