The O’ring 86267069 seals the front cover-housing interface of HC25 Hydraulic Rock Drills, preventing oil leakage and dust intrusion at the drill’s front end. Generic O-rings wear quickly—within 500-600 hours—due to exposure to debris and vibration. This OEM O’ring uses NBR rubber blended with anti-wear agents, improving wear resistance by 40% compared to generic variants. It maintains a tight seal over 800 hours, fitting precisely in the front cover’s seal groove (±0.002mm), and requires mandatory replacement after 800 hours.