Vinyl Flattener is a additive used in Al's Liner to acheive Semi-Gloss and Matte finishes. Al's Liner Vinyl Flattener was originally designed for the military to match the anti-reflective finishes they require.
Directions:
For a Semi-Gloss Finish add 1/2 quart to one gallon Al's Liner Kit
For a Matte Finish add 1 quart to one gallon Al's Liner Kit