Metal end-cap seals combine elastomer core with stainless or Inconel caps to eliminate extrusion entirely. Used in surface and subsea wellheads operating at 15,000–20,000 psi. Caps transfer load directly to groove walls while the elastomer provides energization. They survive unlimited RGD events and temperatures to 350°C intermittently. https://globalsealstech.com/oil-gas-seals/