When casting small details that need high-contrast for microscopic examinations, use the Mikrosil Casting Material Kit. It consists of two easy-to-use tubes, mixing pad and wooden spatula. The large tube contains putty material (available in brown, gray, black and white) and the smaller tube contains catalyst. Brown and gray prefered by tool mark examiners while white and black are used to lift dusted latent fingerprints from rough or textured surfaces.