Create your own pinhole camera with these micro-drilled aperture sheets made of .001"-thick stainless steel. There are 12 1 1/2" square sheets ranging from aperture sizes of .0039" (7.02mm focal length) to .0276" (351.79mm focal length). Includes handy guide listing all the sizes, optimal focal lengths and approximate f/stops. Stick it on an oatmeal box or hotel room window, but most of all, remember to have fun!