Open Seals are used for light to medium duty polypropylene strapping. The most common plastic seal, open seals allow you to place the seal on after tensioning has occurred. For 1/2″ light to medium duty polypropylene strapping either our item # 20230 (EP-1200-12 General Purpose Manual Crimper) or our item # 20250 (PS48L Heavy Duty Manual Crimper) must be used. For 5/8″ light to medium duty polypropylene strapping contact our office for available tool options.