158X Series Type X2 Suppressor Capacitor Cornell Dubilier 158X series Type X2 Suppressor Capacitor is made of metalized polyester, tinned copper clad steel, and feature radial leads in two lengths. The Mallory suppressor capacitor is useful in applications in which damage to the capacitor will not lead to the danger of electrical shock. The UL-1414 and CSA approved capacitor features a flame retardant case and potting end fill that meet UL94V-0 standards.