Stainless Steel closed seals are available in 1/2” and 3/4” widths. They are made from 0.025” thick heavy duty 300 Series Stainless Steel. Closed Seals are designed to be used for diameters of 8’ and over. A standard seal tool is required for use with this particular seal. Closed seals ensure a stronger closure over wing seals on high tension or expansion spring applications.