Sierra 18-9400CAT-4 4-stroke catalyst oil is approved for all 4-stroke applications including outboard, sterndrive, and inboard. It provides superior corrosion protection under extreme conditions as well as industry leading deposit control.

• Meets modern recreational 4-stroke engines with or without emission catalyst systems
• Approved for all 4-stroke applications including Outboard, Sterndrive and Inboard.
• Exceeds all 4-stroke requirements including FC-W and FC-W Cat Compatible
• Formulated to offer maximum corrosion protection
• Advanced lubrication for extended engine life and wear protection
• "ZDDP" anti-wear additive technology
• Prevents phosphorous depletion and extends the emission catalyst life
• NMMA FC-W Certified