Steel Strapping Sealer 13mm. For use in conjunction with our tensioning tool and snap-on seals. Use with 13mm wide seals. Double notch seal. Easy grip handles. Our range of manual sealing tools allow you to securely apply a seal to your tightened strapping, making sure it holds the strapping in place, under tension. We supply individual tools for the width of strapping you are using (13mm, 16mm, 19mm).