I don't even know what Healer's Sashes are, but you sure make them sound useful.
They are this crazy item that lets your party use their healing surges as a pool, rather than individually. So the rogue is running low on healing surges, but the warlock has plenty? No problem, the warlock puts the healing surge in the sash, and the rogue pulls it out with a bonus d6. It's one of the items I rather dislike from the AV.