Nubuck Protector ("Nubuck Dressing") is a non silicone spray that should be used on Nubuck or Suede shoes, or shoes that are a combination of Nubuck or Suede and Leather. It behaves like Scotchgard and makes your shoes stain and water resistant. Non silicone spray is important to keeping the shoe breathable. The can is non-aerosol.
The difference between Nubuck and Leather Protective Spray is that nubuck is more porous and therefore more absorbent- the Nubuck Protector is made to compensate for that. It is very important to re-spray your shoes after you clean them and this should be done, depending on how often you wear them, approximately every two weeks. They should also be sprayed anytime they get wet, but only once they have dried.