C&F Design's medium size, waterproof fly cases are substantially bigger than the small cases but still easily fit into most vest and pack pockets. These fly boxes hold an incredible number of flies for their size, are light weight and very durable. We have been using them for many years and have some that have seen over 20 years of use - they are all just as good as new. 5.9" x 4" x 1.6". Patented design. Made in Japan.