This Woodworks Heavy Duty Yacht Varnish from Johnstone's is specially formulated for use on all exterior smooth planed timber, doors, and window frames. It is a traditional marine-quality varnish that provides a flexible varnish film, which flexes with the timber surface and resists UV attack to protect the timber. This solvent-based varnish can be applied using a roller or spray gun, offering a coverage of 14-16m² per litre.