Wireline pack-off rubber elements use multiple V-shaped or chevron profiles molded from 80–90 durometer HNBR or Viton. These self-energizing seals close tightly around stationary cable and relax during movement, providing reliable 15,000–20,000 psi sealing during logging, perforating, and plug-setting operations. https://globalsealstech.com/product-category/oil-gas-seals/oil-free-lubricated-pump-seals/