These would be awesome for me if not for the tiny, covered eraser. I use the eraser too much and any really dislike any mechanical with that type of design.
jlrvyou cant get refills but those are really only meant for small corrections. I usually use mine in tandem with a BOXY. There is also a click type eraser that is the shape of a pen/pencil which is quite nice.
TheProfosistI use the Clic eraser also, but now more for art than for work. When I used the .5 on old fashioned columnar pads, Pentel sold tiny green erasers that fit into my pencil. Pentel may have some that fit yours.