Kodak are currently packaging their 400 ASA film for pocket instamatic cameras in cassettes that set the meter in cameras that are so equipped to 100 ASA. With small negatives an extra two stops exposure does the image no good at all. Here is a diagram of the film speed setting notch details to use as a guide to trimming the cassette end to set the camera meter to 400 ASA. The notch should be at least 6.5mm (around 1/4 inch) but some extra clearance here will not hurt.