Does what it's supposed to do. Essential gear.
This is a must have, especially if you are new to DE shaving. Wet the tip and apply to your cut for ten seconds or so and you are good to go. I don't think it will leave any white residue, but I have never tried. I usually rinse after I'm done using alum or a styptic. I have had mine for the past five years and it is mostly the same size, just looks a little more like a stalactite than when it was new.