when i do yellow fogs i always go for a generic 12x12 piece of film off ebay. i find removing the fog, taking a 6x12 piece and a hair dryer than stretching it over the fog and trimming with an xacto is the best way to get a perfect fit and finish. i think the film was like $4 or something silly like that. the problem i have with the pre cut pieces is you have to get it centered perfecty and there isnt anything to grip when you heat it up. heat + stretch for the win