In reply to jon:
I bought that for when I was climbing pretty easy Alpine Routes, where gear would not normally be needed, and I was in the habit of taking around 2 or 3 hexes and 2 or three chocks. I rarely if ever used any, so I thought that bit of gear would be OK for the emergency instead of taking 6 other pieces.
In use, the hardness, (the sleeves were steel) meant they would not 'bite' and had minimal surface area in contact with the rock.