We tested many different systems for fly retention. The earliest versions utilized slits in thin plastic sheets that overlayed super-strong rare-earth magnets. While this system worked quite well, the box was heavy and the system was cost-prohibitive. Next we tested many different rubber compounds such as natural rubber, neoprene, and silicone. We settled on silicone for a number of reasons including its versatility and its excellent properties in extreme temperatures. We have designed a fly box insert utilizing inherently sticky, or “Tacky,” silicone sheets that anchor the flies extremely effectively. We have exhaustively tested multiple thicknesses and durometers of silicone to identify the optimum scenario for holding a fly. Through the testing process we also learned that silicone is by nature a non-stick material, so some adhesives are not suited to adhering a silicone rubber to the inside of a plastic box. Fortunately, the adhesive experts at 3M have developed a series of adhesives specifically designed to adhere to silicone.