Seal All Expanding Foam NBS Gun Grade - 12 units per pack - €4.64 per unit. Seal All NBS is a durable and fast curing single-part insulation and assembly foam, developed for sealing and filling joints, seams and connections in building and industry. It is a single-component polyurethane foam and without CFC, HCFC and HFC (ozone-friendly and does not contribute to the greenhouse effect). Available in a 750ml aerosol.