STEWART SYSTEMS PRIMER SEALER GL

Unfortunately this material is not available in an aerosol can.

You must first prep before you apply the ekoprime.

Yes, it is sandable.

That is subjective per the vendor. Typically 300-600 sq feet, but it depends on what you are painting. Maybe less if he is wanting to fill and sand, or maybe more if he is just using it to cover EkoFill for a white base coat.