Ronseal varnish ultra tough interior clear protects against scuffs, scratches and knocks as well as water, household chemicals and heat - ideal for high wear regions. Ronseal varnish ultra tough interior clear is a conventional polyurethane varnish that highlights the natural appearance of wood by providing a mellow finish. Ronseal varnish ultra tough interior clear produces a strong finish for surfaces like window frames, joinery and doors.