Vallejo Desert Tan Base Primer Acrylic Polyurethane 60mlWater based Polyurethane Primer. This Surface Primer can be used directly or mixed with other Auxiliary products like Varnishes, Mediums, etc. It is recomended to avoid mixing Surface Primer with alcohol and/or solvents. Apply with airbrush or brush. This Surface Primer has a selflevelling matt finish of extraordinary hardness and resistence, and does not hide details.