What is it?
A skin-soothing oil – made of sunflower, jojoba, and tea tree oils, along with aloe vera and vitamins A, E, and D – that also coats and protects your blade against moisture and bacteria growth. Smacking a cartridge against a sink to dry it will distort and bend the blades, and even tiny amounts of water will cause blades to corrode. Glopping on a drop of this viscous oil after a shave prevents corrosion completely. Note, however, that HYD Razor Shield uses the controversial preservative BHT, which the FDA has okayed in the low levels found here, but in high levels, it has been traced to liver, kidney, and lung problems in rats and is a potential allergen to humans. Just make sure to use it as directed.

Does it save?
HYD claims of helping one blade stay sharp for a full month of regular shaving rang true. There are up to 90 coatings in a bottle, so you don't have to buy this more than a few times a year.

The coating actually helped the blade to glide more smoothly than even a glide strip – almost like a pre-shave oil that you don't have to put on your face. [$18 for .5 oz; hydformen.com]