The Adams dry fly is a must in any angler's box. It works as a general purpose fly for many situations, an all-around dry fly when any hatch is going on and is the perfect fly for a Callibaetis hatch. Per 3. Sizes: 12, 14, 16, 18, 20. Cancer and Reproductive Harm- www.P65Warnings.ca.gov. Type: Flies.