Ideally, you could provide a flat, smooth part that is at least 2” by 4” so we can use all of our instruments and more easily gauge the match quality. Rounded, textured, and very small parts increase the difficulty in both measuring and evaluating the match quality. We will do our best and work with whatever you have. We commonly match colors from carbon fiber tubes and other non-standard part shapes. We understand that perfect samples are not always available.