From Team Associated:
Whether you race indoor or outdoor, protecting your chassis from premature wear will improve its lifespan and help maintain performance. This Factory Team pre-cut chassis sheet is made from adhesive-backed 18-mil vinyl and offer a protective surface while looking trick with intricate details for that Factory Driver look. Sheets are printed in gloss black and include two extra tail sections to replace as they wear.
For the #91850 +3mm chassis. (Use #91825 for the B6.2D chassis.)