Sierra’s Premium Blend 25W-40 catalyst engine oil is specially formulated to meet the needs of 4-stroke marine engines with catalyst emission systems.

• Sierra premium blend catalyst compatible inboard engine oil
• SAE 25W-40
• 5 quart jug
• Recommended for use with inboard and I/O marine engines with catalyst exhaust systems
• Meets the requirements of modern 4-stroke recreational engines with or without emission catalyst systems
• Developed specifically for the marine environment and the high running stresses marine engines encounter
• Protects internal engine components from rust, corrosion, and from sticking piston rings
• Premium blend features high detergency, anti-oxidants, and antiwear proprties
• ZDDP anti-wear additive prevents phosphorus depletion and extends the emission catalyst life
• Exceeds all 4-stroke requirements including FC-W and FC-W Cat compatible
• NMMA FC-W certified
• Replaces Bel-Ray 99730-BT4