GSL® ALL PURPOSE SEALER (APS) is a sealer that is recommended for use on all GSL® K2.6 or GSL® M3.4 applications to enhance the bond of your underlayment to your adhesive. One coat of GSL® seals the GSL® K2.6 or GSL® M3.4 surface and reduces dusting allowing for the floor covering to be installed. One coat is all that’s required,just mix with water and apply.