The Fly Killer, Fly Shield Four FG4SSS made by Insect a Clear. Insect a Clear are one of Europe's largest insect control specialists, manufacturing both electronic grid and glue board fly killers. Historically, electric grids may have been used through out the food industry to control flying insect infestation. However, there are occasions where the latest glue board technology, as used in the fly shield range, is clearly more suitable. Advantages of this entrapment system include no annoying 'zap', attraction and containment of all sizes of flying insects and debris from exploding flies is totally eliminated.