Signode pneumatic strapping sealers let compressed air do most of the work. They are used to achieve high production on heavy steel strapping, especially when strapping seals are in awkward positions or whenever productivity must be maximized. These labor-saving sealers come in two basic styles. Those featuring pistol grips are lightweight for easy one-hand operation. Diaphragm types are for heavier-duty applications, such as carloading.